The truth is, a free T-shirt changed life for my family.

In 2009, my 10-year-old daughter asked me if she could take part in a health study at her school — because she wanted the free T-shirt promised to the students who signed up. I said yes, not knowing that my answer would change both of our lives.

Health researchers were in Maine to study links between children’s cognitive skills and arsenic in their drinking water. They found that the average IQ scores among Maine school kids with elevated levels of arsenic in their water were five to six points lower than their peers.

What I found out from the researchers who tested our well water is that we were drinking water with arsenic levels nearly three times higher than the level considered safe by the Environmental Protection Agency.

As a mom, I felt so guilty. Arsenic is colorless and odorless, so we had no idea anything was wrong — and I hadn’t ever heard about how important it is to test well water. My two daughters had been drinking and bathing in that water for almost nine years. I’d mixed baby formula, fruit juice and Kool-Aid with that water.

Without knowing it, I’d been giving my babies poison. I worry about the effects it could have had on them every single day.

Now, I’m hoping I can help make sure that other Maine families have access to safe drinking water.

Too many Maine families like mine are unknowingly drinking arsenic, which leaches out of some bedrocks, with their well water. Since over half of Mainers rely on well water for cooking, bathing and drinking, it’s estimated that well water for more than 100,000 Maine people is contaminated by arsenic.

Prolonged arsenic exposure is linked to learning disabilities, cognitive problems, anxiety and depression, and bladder, lung and skin cancers. Arsenic in well water is a silent epidemic, potentially harming families like mine across rural Maine.

The Legislature last month overrode the governor’s veto of a bill to expand outreach and education about this silent epidemic in Maine. By helping moms like me and many others learn we need to test our well water, it will dramatically boost the number of people who test. Currently, less than half of Mainers relying on wells test their water.

That law was an important first step. But once a family finds out they have arsenic, it costs hundreds or even thousands of dollars to be able to get it out of their water. We were lucky that we could afford our filtration system, which cost a few hundred dollars. Some people are struggling to put food on the table, and they don’t have a few hundred dollars to spare. Others need more expensive treatments; I have one friend who got an estimate that was over $5,000, which just wasn’t affordable.

I can’t imagine having to feed my children poison-laden water after I found out there was contamination. But lots of families don’t have a choice.

A second bill passed in this session — LD 1263 — would help make sure all families in Maine can feed their children safe drinking water, whether or not they come from means. Sponsored by Sen. Joyce Maker, R-Washington, it supports funding to help lower-income families pay for well water treatment.

With strong bipartisan support, the Legislature approved putting aside $500,000 to help all Maine families access safe drinking water, using funding that is available at no additional cost to taxpayers.

I was excited at the news, cheering it with my kids.

But then I learned that Gov. Paul LePage may veto this law.

If he does, here’s my message to Maine legislators: Moms like me are counting on you to override the veto, to help us protect our children from poison in their drinking water. No family should be denied safe drinking water because of a price tag.

My idea for a new T-shirt for my daughter is one that says this: “All Maine families deserve safe and affordable drinking water.”

Wendy Brennan is a mom of two. She lives in Mt. Vernon.