The Home Inspector

Reuben Saltzman is a second-generation home inspector with a passion for his work. Naturally, this blog is all about home inspections and home-related topics in the Twin Cities metro area. In addition to working at Structure Tech, he is also a licensed Truth-In-Sale of Housing Evaluator in Minneapolis, Saint Paul and several other cities.

Siding Stains: Why Do Houses Cry?

Posted by: Reuben Saltzman under Home Improvement Updated: November 11, 2014 - 6:07 AM

I recently had a reader email this question, and thought it would make for a good blog post:

We get brown water stains on our siding over the winter, but they mostly go away over the summer. Will you perform an inspection for those stains only (not a whole-house inspection)?

Stains on siding

While we're happy to conduct single-item inspections to troubleshoot problems exactly like this, this particular situation is so common that it probably doesn't need an inspection.  The stains on the siding are the result of moisture; that much is for certain.  When water runs through the wood and wall sheathing, it picks up tannins in the wood and leaves dark stains on the siding.  If the home experiences ice dams and the stains start at the soffits and run down the siding, they're probably the result of water leaking through the roof as a result of the ice dams.  The illustration below from The Ice Dam Company shows the path of the water.

Anatomy of an ice dam

Here's an extreme example of what you might see on the side of the wall during the winter:

Ice on wall

Here's a close-up photo showing some ice turned brown from the tannins in the wood:

Brown Icicles

Here are a couple of photos showing what stained siding looks like after all the ice is gone.

Stains on siding below soffit

Stains on siding below fascia Gable Wall

So ice dams are one possibility.  In this particular case, I got a little more information from the homeowner and decided the stains probably weren't the result of ice dams.  When stains also show up on gable walls, they definitely aren't the result of ice dams.

When siding stains appear in random areas during the winter, it's the result of moisture migrating through the walls during very cold weather, condensing as frost, then melting again once the outdoor temperature warms up.  That's the long and short of it, but there are a number of things that will increase the potential for water stains to show up on siding.

Stains on vinyl siding

Cold Weather

The colder it is outside, the greater the potential for frost accumulation in the walls and attic.  When there is an extended period of unusually cold weather like we had last winter, the potential for frost accumulation will increase as well.

Humid Air

The more humid the air in your home is, the greater the potential for frost in the walls and attic.  Do what you can to lower humidity levels; the most obvious "no-duh" thing would be to turn off your whole-house humidifier if you have one.  A few other ways to lower indoor humidity levels are:

  • Install timers on your bathroom exhaust fans that will run the fans for an hour at a time, and use the fans.
  • Install bathroom exhaust fans in bathrooms that are used for showers or bathing if not present.
  • If the kitchen hood fan exhausts to the exterior, use it while cooking.
  • If you have too many plants (or weeds) in your home, fix that.
  • If you have a crawl space with no vapor barrier, fix that.  Crawl spaces with dirt floors are major contributors to indoor humidity.
  • If your home doesn't have a ventilation strategy, add one.  To understand what that means, please read this excellent article by Allison Bailes at the Journal of Light Construction web site: Choosing a Whole House Ventilation Strategy.
  • Read the article I just linked to above.  Seriously.  This will make the rest of this blog post make more sense.

Combustion Air Duct Connected to the Furnace Return Plenum (AKA - "Supply Only" ventilation)

Combustion Air Connected to Return Plenum

In Allison Bailes' article above, this would be described as a "Supply Only" ventilation system for the home.  When the blower fan on the furnace runs, it pulls air into the home via the duct that runs to the exterior of the home.  This puts the home under positive pressure.  Of course, all of that air coming in needs to leak back out... somewhere... right?  Of course it does.  It leaks through a million little holes in the walls and ceilings.  It leaks through outlets, switches, and countless other penetrations.  This is how moist air gets into the walls.  This is a bad way to ventilate houses in Minnesota.  Check out my blog post on this topic for more info: Combustion Air Duct Connected to Return Plenum

Improperly Balanced HRV/ERV

If an HRV or ERV isn't properly balanced, it can put the house under positive pressure.  This increases the potential for air to leak into the wall cavities.

Unbalanced Ductwork

Unbalanced HVAC ductwork can cause pressure problems.  Leaky or excessive return openings in the basement can put the basement under negative pressure, while the upper levels are put under positive pressure.  As I mentioned in my blog post on frost in the attic, one simple test to find out if your basements “sucks” is to position a door to the basement about 1" away from being closed, then turn the furnace fan on.  If the door closes by itself, it’s an obvious sign that the ductwork is not properly balanced.

There are more factors than these, but these are a few of the most obvious ones.  If a home has never had stains on the siding in the past but stains recently started showing up, you're probably scratching your head wondering why, right?  The simple answer is that something changed, and the most likely change was that you decreased the ventilation in your home by accident.

Turning off or disabling an HRV (air exchanger) would be an extremely obvious example, but that's a little too "on the nose".  If that happened, you already know what you did.  A far more likely but less obvious cause for decreased ventilation in a home would be replacing an older 80% efficient furnace with a new high efficiency, sealed combustion furnace.  That will make for a major unintended change in ventilation; check out my blog post from over five years ago on that topic: New High Efficiency Furnace, New Moisture Problem.

Another common cause of decreased ventilation is having air sealing performed in the home - especially in the attic.  Attic air leaks are also known as attic bypasses.  This is actually something that is now required by law in Minnesota when having attic insulation added: Minnesota Department of Commerce: “Beware the Insulation Contractor Who Does Not Include Air Sealing”.  When these air leaks are sealed, less air leaves the home, so less air enters the home.  That means a decrease in ventilation, which means new problems will probably show up... such as stains at the siding.

Side note: I've been recommending Cocoon for insulation jobs for the past couple of years, because they take all of these factors into account when they work on homes.  Check out their guest post on my blog for more on this topic: Unintended Consequences of Adding Insulation.

Author: Reuben SaltzmanStructure Tech Home Inspections 


Moisture Testing Homes with Vinyl Siding

Posted by: Reuben Saltzman under Real Estate, Home Improvement, Real Estate Updated: November 4, 2014 - 6:31 AM

While the majority of our moisture testing is done on stucco homes, moisture testing isn't just for homes with stucco siding.  Moisture intrusion can happen with any type of siding, and it's always an expensive repair when left unchecked.  Just recently, some friends of mine expressed concern about some dirt that started showing up below the corner of their living room window, so they asked me to take a look.  The photo below shows the "dirt" they were talking about; click on the image to see a larger version.

Dirt below window

Can you guess what caused it?

The title of this blog post probably gives it away, but before I show photos of the rotted wall, let me first explain all of the stuff that went wrong.  To start, here's a photo of the front of the house.  It's a little tough to see through the tree, but there are no gutters at the upper section of the roof, and the valley at the upper roof dumps water onto the lower roof.  From there, the lower roof is supposed to direct water into the gutter.

Front of house original

If there had been gutters installed at the upper portion of the roof, all of that water would have been dealt with, but instead the lower roof gets pounded.

Kickout FlashingAt the lower portion of the roof, there should have been a piece of kick-out flashing installed where the roof ends above the window, but there was none present.  This allowed water that ran down the roof/wall intersection to leak in behind the vinyl siding.

Finally, there was no water-resistive barrier installed behind the vinyl siding.  As I mentioned in my blog post about how to inspect your own siding, vinyl siding isn't designed to be watertight.  It's only supposed to keep most of the water out.  It works because there is supposed to be a weather-resistive barrier installed behind the siding, such as Tyvek®, which is a brand name that is somewhat synonymous with house wrap.  Unfortunately, water-resistive barriers weren't specifically required by the MN State Building Code until 2003, so it was pretty much hit and miss up until then.  In this particular case, it was "miss".  Without a water-resistive barrier, all of that water that leaked in behind the siding ended up saturating the wall sheathing and leaking into the wall cavity, where it caused major damage.

I did some moisture testing around the window to confirm my suspicions, then we took the siding off to get a good look at the damage.

Water damage behind vinyl siding2 Water damage behind vinyl siding3 Water damage behind vinyl siding4 Water damage behind vinyl siding5

Nasty, huh?  Thankfully it was just vinyl siding, which does a pretty good job of allowing the wall to dry out. If this had been stucco siding, the damage likely would have been much more extensive and the repairs much more expensive.

Remember, the only visible evidence of this water damage was the little black flecks that had made their way through the window and landed on the carpet.  I suspect those were little pieces of rotted wall sheathing blowing into the home during periods of heavy wind, but I'm not 100% sure.

This is the type of damage that home buyers try to avoid when buying any home, and this is why some home buyers choose to have moisture testing performed on homes with vinyl siding.  Vinyl does a great job of hiding this kind of damage.  While moisture testing on stucco homes is considered an invasive inspection and requires special permission from the homeowner, moisture testing of vinyl sided homes is done by using a non-invasive surface scanner to quickly scan large areas of the siding for moisture intrusion, and then followed up with pin-probe testing behind the siding to verify the results of the surface scanner.  The siding is then popped back into place, leaving the siding in it's original condition.  This is a non-invasive inspection that requires no special permission from the homeowner.

Included below is a short video clip showing Antonio and I performing moisture testing on a 2007 built townhome that had moisture intrusion below the deck. 

If you're buying a home with vinyl siding or you already own a home with vinyl siding and there is concern about water intrusion, have moisture testing performed.  Vinyl sided homes with no moisture barrier should always raise concerns, but as seen in the video clip above, moisture intrusion can still occur when a moisture barrier is present.  For information about how moisture testing is done on other types of siding, click here:

Author: Reuben SaltzmanStructure Tech Home Inspections


How To Inspect Your Own House, Part 8: The Furnace

Posted by: Reuben Saltzman under Home Improvement Updated: October 27, 2014 - 4:34 AM

While a thorough furnace inspection is best left to a pro, there are a few basic things that homeowners can inspect to help prevent safety and operational problems.

To inspect your furnace, start by taking a look at the filter and replace it if it's dirty.  Religiously replacing the furnace filter is one of the easiest and most important things that you can do to help prevent problems with your furnace. The filter isn't there to clean the air that you breathe; it's there to keep the furnace clean.  A dirty filter means restricted air flow, which means less heat being dissipated from the heat exchanger.  This can cause the furnace to run hotter than it's supposed to, which can lead to premature failure or complete shut-down of the furnace.  This is very important.

If you have a combustion air duct coming into your furnace room, make sure it's not blocked.  I gave several examples of blocked combustion air ducts in my blog post about combustion air duct problems and solutions.  Here are some self-explanatory photos from that post:

Blocked Combustion Air Duct Combustion air covered with duct tape Restrictive combustion air duct box Restrictive combustion air bucket Combustion air duct J Combustion air duct with bucket

Next, check to see if your furnace is operational.  Set your thermostat to heat mode and turn up the heat about five degrees warmer than what the thermostat thinks the temperature is.  Now head to your furnace and make sure it fires up.  If the furnace doesn't fire up, here are a few more items to check:

  • Check the service switch to make sure it's on. This is typically a light switch that's either mounted to the furnace or located on a wall very close to the furnace.  If this switch is off, the furnace won't run.
  • Check the circuit breaker or fuse at the main electric panel.
  • Test or replace the batteries in the thermostat.
  • Make sure the blower fan cover is in place.  If the cover is removed, a safety switch on the blower compartment should prevent the furnace from turning on.

Older furnaces will typically fire up instantly, while newer furnaces often go through a startup cycle, where the blower fan runs for a while, the draft fan runs, then the furnace fires.  If the furnace is working properly, the flames will fire up and stay ignited.  If the flames go on and then off again right away, there's a problem with the furnace and it's time for a service call.  The video clip below shows a quick example of this happening: 

Once the furnace fires up normally, it should stay running without shutting off until the thermostat is satisfied.  If the furnace runs for a few minutes and then shuts off before satisfying the thermostat, it's short-cycling, which is a problem.  This could be caused by an oversized system or a thermostat located in a poor location, like right above a heat register.  A dirty furnace filter can also cause a furnace to short-cycle, but you already checked that, right?

Now go around your house and check to make sure the supply registers are open and unobstructed, and make sure there is warm air coming out of them.  If too many registers are closed off or obstructed, the furnace probably won't operate properly.  Check out this post at the Energy Vanguard blog for more information on that topic: Can You Save Money by Closing HVAC Vents in Unused Rooms? 

hand on furnace plenum

After the furnace has been running for about fifteen minutes, put your hand on the ductwork above the furnace.

If everything is operating normally, the ductwork will be hot, but not uncomfortably hot.  You should be able to leave your hand on the ductwork without feeling any pain.  If the plenum is uncomfortably warm or you'd like to conduct a more technical test, check out my blog post titled A DIY Test For Furnaces.

Those are the basics, but it's still a good idea to have your furnace professionally inspected annually.  More on that topic here: Are Annual Furnace Inspections Really Necessary? Click on any of the links below to see the past topics in this series:

Author: Reuben SaltzmanStructure Tech Home Inspections


How To Inspect Your Own House, Part 7: Protect Your Water by Preventing Cross-Connections

Posted by: Reuben Saltzman under Home Improvement Updated: October 20, 2014 - 6:01 AM

The most important job of any plumbing system is to deliver clean water, and to keep that water clean from sewage and other contaminants.  This makes up the first and second of the basic plumbing principles in the Minnesota State Plumbing Code, which read as follows:

A. All premises intended for human habitation, occupancy, or use shall be provided  with a potable water supply which meets the requirements of the commissioner of health. Such water supply shall not be connected with unsafe water sources nor shall it be subject to the hazards of backflow or back-siphonage.

B. Proper protection shall be provided to prevent contamination of food, water, sterile goods, and similar materials by backflow of sewage. When necessary, the fixtures, device, or appliance shall be connected indirectly with the building drainage system.

A large section of the plumbing code is dedicated to protecting our potable water supply, so it's a good idea to check your own home for some of the most obvious violations and fix them.  Truth-In-Housing Evaluations have a big focus on protecting the municipal water supply, and homeowners are typically required to repair conditions that could contaminate the potable water supply.  I've already blogged about many of these conditions, so I'm pulling content from many of those past posts to put all of the information together into one post.

Check out this old video clip for some good information about the importance of protecting the municipal water supply.  The first minute and forty-five seconds waxes on and on about who made the video possible, then they get to the actual content, so here's a link to 1:46 into the video:

As mentioned in the video, any potential cross-connections are potential sources of contamination. 


A cross connection between the water in a toilet tank and the potable water supply can be made if the toilet fill valve or toilet ballcock is improperly installed.  There are three most common types of toilet fill valves; the old style ball-cock, the new style fill valve, and the clam-shell type.  The ballcock relies on a floating ball to shut off the water supply when the water in the tank gets high enough.  The approximate height at which the fill tube connects to the ballcock is considered the "Critical Level" line, and it needs to be at least 1" above the top of the overflow tube.  The diagram below illustrates this.

Standard Ballcock Air Gap

By far the most popular type of fill valve today is the type with a float attached to the stem of the fill valve, which is shown in the diagram below.  Again, the critical level line needs to be 1" abot the top of the overflow tube.

Toilet FluidmasterBallcock

Here's a short video clip that I made many years ago, showing homeowners how to adjust the height of the fill valve in an existing toilet.  One quick warning though: the installation instructions for these fill valves actually says to adjust the height of the fill valve before it's installed, and that the little ring on the bottom shouldn't be moved at all, as this is what holds the assembly together under pressure.  Whatever.

A far less common type of fill valve is the clam-shell type, which sits at the bottom of the toilet tank.  These valves create a potential cross connection and just shouldn't be used.

Clamshell toilet fill valveClamshell Toilet fill valve

While the risk of contamination to the potable water supply is fairly low, I suspect most people would prefer to not drink the water in their toilet tanks if they didn't have to.  While on the topic, here's a 'fun' photo I took during a home inspection a couple of years ago.  I flushed the toilet as I was filling the bath tub, and the filthy water in the toilet tank was siphoned into the water going into the tub, instantly turning the tub water black.

Contaminated tub water

Gross, huh?  That's why the guts of the toilet matter. 

Outside Faucets, Utility Sink Faucets

Any time a garden hose can be attached to a faucet, the faucet should be protected from a cross connection.  On older faucets without a built-in vacuum breaker, this could be achieved by installing an external vaccuum breaker, as shown below.

Vacuum Breaker 1011

Note: the vacuum breaker shown above doesn't technically meet code in Minnesota, however, Minneapolis and Bloomington allow these vacuum breakers for their Truth-In-Sale of Housing / Time of Sale evaluations.  More on that specific topic here: Cheap Vacuum Breakers Don't Meet Code.

Every faucet I've seen on new construction homes for the past several years has come with built-in backflow prevention, and can be identified by a slightly longer stem.  The photos below show examples of faucets with integral backflow prevention.  These faucets don't need an external vacuum breaker.

Frost-free sillcock with integral vacuum breaker Sillcock with integral vacuum breaker

Utility sink faucets with threads that will accept a garden hose should have an exterior vacuum breaker installed.  Don't install vacuum breakers at the hot and cold water valves for the washing machine though; washing machines are already built with an internal air gap. 

Bath Tub Faucets

If you have an old bath tub with a faucet located inside the tub, such as the one pictured below, you have a potential cross connection.  Don't mind the height of the overflow; the overflow is not the same as the spill line, as a clogged drain would also mean a clogged overflow.

old faucet

One way to correct this issue is to replace the faucet.  A proper faucet for a clawfoot tub will have the opening of the faucet spout located well above the spill line of the fixture, as shown below.  I found a decent selection of replacement faucets at .

Code-Compliant Faucet

If you like the faucet you have or you just don’t want to change out the faucet, another option is to have dual in-line check valves installed on the water supply pipes.  These valves will prevent potentially contaminated water from flowing back into the potable water supply.  If you choose this method, make sure the check valves are accessible; when the next inspector comes through, they’ll probably be looking for them. 

Bathroom Sink Faucets

Very old bathroom sink faucets that have openings below the spill line of the fixture create a potential cross-connection.  This usually happens with the type of faucets shown below, where there is a separate faucet for both the hot and cold water.  My tape measure is sitting on top of the spill line of the fixture to show the relationship of the faucet openings to the spill line.  The faucet openings should be at the same height as the top of my tape measure to create a 1" air gap.

Cross connection at bathroom sink

This is a bad setup to start with, because there is no way of tempering the water coming out of the faucets unless you want to fill the sink... and who wants to do that?

The best fix is to replace the faucets with a single faucet, which may also require replacement of the sink.  Another option is to install check valves on the water supply pipes.

One non-recommended way to fix this cross connection is to bend the faucets up a little bit to create an air gap.  I say non-recommended because there is a risk of permanently damaging the fixtures, but I bring up this fix because I've seen it done many times. 

Hand Showers

Hand Shower

Hand showers that can sit in bath tub or shower water create a potential cross-connection.  Many hand showers already come with built-in backflow prevention, but not all.  The most obvious way to prevent a cross-connection at a hand shower is to replace the hand shower with a standard shower head that doesn't have a hose.

Vacuum Breaker for Hand ShowerIf you don't want to lose your hand shower, install a vacuum breaker with a 1/2" thread, as shown at right.  This device installs in-between the pipe coming out of the wall and the shower head.

As with most other potential cross-connections, installing dual inline check valves on the water supply lines that feed the shower would be an acceptable fix as well, but it's a lot more work.

If you live in Saint Louis Park or Bloomington, you’ll have to fix this when you have your pre-sale inspection done.  For Truth-In-Sale of Housing evaluations, Minneapolis only requires that handheld showers have a hook to hang on that will keep the shower head above the spill line of the fixture. 


If the dishwasher drain hose is improperly installed, there's a potential cross connection at the dishwasher.  The Minnesota State Plumbing Code (section 4715.1250) actually says that dishwasher drains are supposed to have an air gap, which is this ugly thing that sits on top of the counter, as shown in the diagram below (courtesy of CodeCheck).

Dishwasher air gap

We don't see too many of those here in Minnesota though (thank goodness), because the plumbing code then goes on to say that a residential dishwasher is allowed to connect directly to a garbage disposer or sink tailpiece as long as "the drain line is fastened as high as possible under the countertop."  The diagram below shows a nice example of this:

High loop at dishwasher drain

Nevertheless, here's a common installation that we find, even while doing new construction inspections:

Improper air gap at dishwasher drain hose new

Tsk tsk.  As you can see, the dishwasher drain hose isn't even looped as high as the bottom of the sink... and this was from a brand new home in Plymouth that we inspected a week ago.  For more discussion on this topic, check out my old blog post on dishwasher drains

Water Softeners

The discharge hose on a water softener needs to have an air gap at it's termination; it should never connect directly to any fixtures or drains.  The two most common places to terminate a water softener discharge hose are at a utility sink or a floor drain.  There are about a bazillion ways to create an air gap, so here are a few nice examples.  This first diagram shows the instructions that come with a water softener.  Easy enough.

air gap at water softener drain

The only problem with the setup shown above is that it will make a big ol' mess of the floor.  This next one is a pre-manufactured solution called the Handy GaP, which will prevent water from splashing all over.


If the water softener discharges to a laundry sink, simply figure out a way to make the hose terminate 1-1/2" above the spill line of the sink.  The photo below shows one example of this.

water softener air gap at sink 


In Minnesota, the minimum type of backflow prevention device required for a boiler in a one or two-family home is a double check valve with an intermediate atmospheric vent (DCVIAV).  This valve must be installed on the water supply line that feeds the boiler.  The image below shows an example of this device.

Double Check Valve with Intermediate Atmospheric Vent

For anything other than a one or two-family home, a reduced pressure zone (RPZ) valve must be installed.  This valve is also needed if any chemicals are added to the system, such as glycol.

RPZ Valve

If you have a boiler at your home but you can't find one of the two valves pictured above, you ain't right. This is a repair that's best left to a plumber.


These are the most common cross-connections that home inspectors find.  If you have any of these cross-connections in your own home, your "good citizen" duty is to fix them.  Next week, the topic will be inspecting your furnace. Click on any of the links below to see the past topics in this series:

Author: Reuben SaltzmanStructure Tech Home Inspections


How to Inspect Your Own House, Part 6: Plumbing

Posted by: Reuben Saltzman under Home Improvement Updated: October 13, 2014 - 5:24 AM

If it's leaking, fix it.  The end.

Ok, I'm kidding.  Today I'm going to share some home inspection tips and tricks that homeowners can use to identify plumbing problems.  You'll want to use a good flashlight for your plumbing inspection, as a lot of this work involves looking underneath sinks and tub drains.

Bathroom Sinks

Most homeowners already know about the more obvious leaks under bathroom sinks, but to really test your sink for leaks, fill the sink with water and then let it drain all at once.  This test will force a large slug of water through the drain, and will often identify leaks that wouldn't otherwise be seen.  Carefully watch the drain while performing this test.  One of the most common leak locations at bathroom sinks is at the drain stopper; fixing this leak is usually as simple as tightening the nut.

Note: if your drain goes "glug glug glug" after the water has drained out, you're hearing air getting siphoned through the trap, which indicates a problem with the venting.  Click this link for more information on that topic: Plumbing Vents: Why Houses Need Them.

If the bathroom sink drains slowly, it's usually the result of hair in the drain.  Fix this by pulling the hair out with a Zip-It tool.  What's a Zip-It?  I'm glad you asked.  It's an inexpensive, effective, and easy-to-use drain cleaning product invented by a Minnesotan.  Click the following link to find out, but prepare yourself to see some absolutely disgusting photos of hairballs removed from drains:


Stand at the toilet with the front of the bowl between your legs, and give the toilet a little nudge with your shin to make sure it doesn't rock or swivel.  A loose toilet can lead to a leaking toilet.

Flush the toilet several times times and check behind, around, and under the toilet (if possible) for any leaks.

If you have a toilet that clogs frequently, replace it.  I recommend using Consumer Reports to help decide on a toilet.  Their team tirelessly tests toilets in the most tasteful manner possible to figure out which ones have the best flushing ability.  I've trusted them in the past, and they haven't let me down.  I'll leave it at that.


I wrote a whole blog post about identifying shower leaks over five years ago, and not much has changed since: .

To inspect bath tub drains, first make sure there is access to the drain.  Sometimes this will be in the form of a large access panel in the room behind the tub, sometimes it will be an access panel at the ceiling below, and sometimes it will simply be a return register grill screwed to the wall that covers a hole in the wall.  The photo below shows a comically small access hole for the bath tub drain at a recent new construction inspection in Otsego.

Comically Small access hole

This next photo shows a more traditional, old-school access panel behind a basement bath tub.  The faucet was leaking profusely, but there were no rooms below, so the homeowner didn't know it was leaking.

Leaking bath tub faucet

Once you've established that there is access to inspect the bath tub drain, fill the tub with water all the way to the overflow, and watch the overflow from the back side to make sure that water doesn't leak out.  A leaking bath tub overflow can lead to a big mess, and this is one test that is specifically excluded by home inspection standards of practice.  After you've made sure the overflow doesn't leak, pull the drain at the tub and make sure the drain itself doesn't leak.  If there are any leaks at the faucet, you'll probably find them while doing this test.

The other common issue with showers and tubs is a slow drain, again, usually because of hair.  Get a Zip-It.

Kitchen Sink

For the kitchen sink, fill up both sides of the sink with water, pull the stoppers, then immediately turn on the garbage disposer if present.  This will force a lot of water through the drain all at once, and will often identify leaks and drain problems that nobody knew about.  Sometimes this test will even force water to shoot out of a crack in the side of the garbage disposer.

Crack in Disposer

If there's a problem with the sink drain, water will typically back up on the side of the sink that doesn't have a disposer, as shown in the photo below.

Water backing up in sink

The culprit is typically old galvanized steel drain lines, which accumulate sediment on the insides of the pipes, making the internal diameter smaller and smaller over time, to the point where the fixtures drain very slowly, or not at all.  The fix for this condition is to replace the drains, which is an expensive repair.

This test on the kitchen sink will also sometimes expose problems that show up in other areas; we've caused water to back up through reverse osmosis water dispensers, basement bathroom sinks, basement floor drains, basement laundry sinks, and basement standpipes by doing this test.  After conducting this test, go downstairs and make sure none of the other plumbing fixtures have backed up.  If they have, there's a problem with the drains.

I have a few short clips of these things happening in my "47 Home Inspection Issues in Under 3 Minutes" video.  At the 12 second mark, you'll see a basement bathroom sink overflowing (I had fun cleaning that up), a standpipe overflowing (Milind had fun cleaning that up), two more clips that aren't related, then a water dispenser overflowing at a kitchen sink.

Floor Drains

The most common issue with a floor drain is a missing clean-out plug.  This will allow hazardous, stinky sewer gas into the home.  For information about how to identify and correct this condition, check out my blog post on floor drain basics.

Side note: floor drains are usually the focus of attention when a main building drain is clogged.  I've received more comments on my blog post on floor drains than any other post.  Most of the comments were from frustrated homeowners dealing with clogged main drain lines.  If the main drain line in your home is clogged, water draining from the upper fixtures will starting backing up out of the lowest fixture.  The lowest fixture is almost always a floor drain, so that's where water comes out.  This really has nothing to do with the floor drain; it's just were the problem manifests itself because the floor drain is the lowest fixture.

Water Heaters

Water Heater Draft HoodI've already blogged about water heaters ad nauseam, so I'll make this short and sweet.  Perhaps the easiest thing to check on your water heater is to make sure it's set to a safe temperature, which is about 120° - 125° Fahrenheit.  If your water heater has a draft hood (pictured at right), make sure your water heater drafts properly under a worst-case scenario.  Also, check the relief valve discharge tube for signs of leaking.  Leaking can lead to corrosion, and corrosion can lead to failure (and failure can lead to the dark side).

If your water heater is leaking from the bottom, it's time for a new water heater.

Here are several other blog posts related to water heaters:

That's all for this week.  Next week I'll show you how to identify and correct the most common plumbing cross-connections in your home. Click on any of the links below to see the past topics in this series:

Author: Reuben SaltzmanStructure Tech Home Inspections



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