At an Apple Valley Rotary meeting some years ago, Steve Mattson heard that children in Haiti were dying because of contaminated drinking water. He knew he had to do something to help.

That was 1999, and since then the Rotary Safe Water Plus program has raised more than $3.5 million with Mattson’s help and encouragement.

“There are certainly well over 150,000 children who have access to safe, clean drinking water who didn’t have it before,” said Ron Axel, a retired dentist who worked with Mattson on the project. “Steve was a big guy in stature, but he had this even bigger heart.”

Mattson, who helped found a successful financial services firm and donated to numerous causes, died on Saturday. He was 65.

The clean water project was so successful that other Rotary chapters wanted to know the secret of its success.

“More than anything the secret was Steve,” said Mattson’s wife, Mary. “Steve always wanted to be there to help. Sometimes it was advice, or a kick in the butt. But he always would do what he thought was right.”

Friends say Mattson tried to follow the example that his parents taught him in Cokato, Minn., the town where he grew up and developed lifelong values. “He got the best of both his mom and dad,” Mary Mattson said. “He learned from his parents that you always take care of those that need help.”

Although he had achieved success in the Twin Cities, Mattson kept his ties to Cokato. He remained friends with many from his school days there and even maintained membership in the same Lutheran church he attended as a child.

“Way back in the day, he said that he made a pact with God. Basically, if he is able to make money in his life he would be a good steward of it in terms of giving back to what he could,” said his son, Andrew Mattson. “Even when he was nearing death, the last major thing he got out of the house for was to go and be part of a charity event.”

Mattson helped causes large and small. He once bought a used car for a man whose auto had broken down and was riding to work on a bicycle. He also paid for the care of a man in an Alzheimer’s home who had run out of money.

“He would just do things like that,” said Mary Mattson. “It was always very quiet and he never expected anything in return.”

Mattson was one of five partners who in 2002 founded Northland Securities, a Minneapolis firm that now employs 200 workers. “He wanted a company where we could all row the oars together,” said CEO Randy Nitzsche.

Mattson specialized in helping cities and other local governments raise money through bond issues.

“He said he never wanted to retire,” said Mary. “He always enjoyed going to work. There’s few people that can stay in the same line of business for 42 years and not be tired of it.”

A devoted fan of Minnesota sports teams, Mattson was also a lifelong poker player, belonging to the same poker club for 40 years.

“Everyone always imagined that he had a lot of money on the table, but if he had to double down or it got up to $20, he began to sweat,” said Mary. “To him it wasn’t an addiction. Steve was like a walking computer and numbers was the name of the game.”

Family members also recalled Mattson’s sense of humor.

“He said ‘If you marry me I will make sure you will laugh every day,’ ” Mary Mattson said. “I was very fortunate to have met him.”

In addition to his wife and son, Mattson is survived by daughter Chunny Daiker of Rogers and four grandchildren. Services are scheduled for 1 p.m. Friday at Cedar Valley Church, 8600 Bloomington Av. S., Bloomington.