Avoid sushi. Limit caffeine. Skip the soft cheeses. Your OB will tell you all of this. But nobody — not your doctor, not your water utility, not any real estate platform you checked before buying your home — mentions the tap water. The one thing you're told to drink more of.

My name's Marissa and I'm a hydrogeologist who values clean water. I'm also a mom to a perfect one-year-old who was born with a congenital heart defect and will need open heart surgery next year. I remember the moment the doctor told me he had a defect. I was 35 weeks pregnant. I knew something was wrong when the ultrasound tech spent a longer than usual amount of time on his heart. I cried when I pictured my sweet baby who I hadn't met yet laying on a hospital bed getting open heart surgery. The doctor said it was common, that his son had one and was just a normal kid.

"Did I do something to cause this?"

"It's highly unlikely — all we know is heart defects are caused by a mix of genetic and environmental factors."

All I heard was "we don't want you to feel worse so we'll blame it on something else."

My son was born 3 weeks later in the best hospital, with the best doctors and nurses, perfectly perfect. He goes in every 6 months for an EKG and an ultrasound to monitor the defect. It's not getting any bigger, or smaller, and we're just waiting for his tiny heart to be big enough to operate on. Watching him grow and play has distracted me from thinking about it too much.

I started building WaterScore about a month ago. I had the idea years ago - water quality by address lookup - people should be able to see what's in their drinking water easily, and they should be able to know if a house they're interested in is on municipal water or will require a well. It's a passion project. I spend far too much time on it. I believe in the cause - People should not have to rely on being able to read the insanity that is utility-generated PDF reports to understand what they're drinking every day.

Consumer Confidence Reports, or CCRs, are required to be sent to you every year by your local municipal water utility. They're filled with pages upon pages of text — messages from the director, photos of the leadership team, landscaping tips, explanations of where your water comes from and why you should feel good about it. Buried deep in those reports are over-designed tables of data — made to look pretty so you know your tax money is being put to good use. If you try hard enough you can read some perfectly formatted paragraphs of very small font filled with scientific jargon about what the 90th percentile measurement means, or what TT stands for, but most people never even make it to the data table. And if they do, as long as the graphic designer didn't choose bright red as the violation highlight color, they'd never know to be worried anyway.

These reports are completely, embarrassingly, incomprehensible. There's even a peer-reviewed journal article explaining how awful they are at doing the one job they have, which is to communicate water quality to the people drinking the water (Iuliano et al., 2024). But here's the thing: even if you could read them perfectly, you'd still walk away thinking you were safe. Because the federal limits they're comparing against weren't set to protect your baby. They were set to be affordable for your water system.

The EPA maximum contaminant level for arsenic in drinking water is 10 µg/L. The CCR for my town - Socorro, NM - reports it at 9 µg/L. I always did a double take at that number and thought "hm, suspiciously close, but I guess under the limit is safe" and moved on with my life. I think it would've been nice if the graphic designer added "arsenic at this level has been linked to congenital heart defects — if you're pregnant, consider a reverse osmosis filter" next to that row. But I guess that's not important enough information to include in the sea of other very important information provided in these very understandable documents.

A 2022 nationwide Danish cohort study of over one million live births found that maternal exposure to arsenic in drinking water at levels as low as 0.5 µg/L — eighteen times below the US federal limit — was associated with increased risk of congenital heart disease, including atrial septal defects (Richter et al., 2022). My son was born with an atrial septal defect.

The EPA set that limit based on what's affordable for water systems to treat, not on what's safe for a developing heart.

A reverse osmosis filter costs less than a crib. An atrial septal defect costs $25,000 to repair — that's before the years of cardiology visits, echocardiograms, and the work you'll miss holding your child's hand on surgery day. No one told me to buy the filter.

Now let me be clear — I am not saying definitively that the high arsenic (but below MCL) level in my drinking water caused my son's heart defect. I am saying that the research is there and that people deserve to know. Pregnant women should know they can take even the smallest action, like buy a simple water filter, to feel like they did what they could to prevent their unborn child from needing open heart surgery at 2 years old.

I built WaterScore because I deserved to know I could do something, and everyone else does too. Check your water →.