Why Your City’s Water Report May Not Tell the Whole Story

Every molecule of tap water you drink is coming at the end of an epic and highly complex engineering journey. Each sip starts in a river’s watershed or in an underground aquifer, before going through several layers of treatment and filters weeding out debris, bacteria, and contaminants before dripping into your cup.

Water quality is tested at almost every stage of this process, findings local municipalities usually summarize for the public in tidy drinking water reports. But there’s a few crucial steps that can easily escape quality control procedures, mostly during the so-called “last mile” between a water distribution center and your kitchen sink. It’s a stretch that could be lacing ostensibly safe tap water with potentially harmful contaminants.  

Water has to go through “miles and miles of pipes before it gets to your house, and who knows what happens to it during that journey,” says Rick Andrew, a water filtration expert and ROSE scientific advisory board member. 

Every individual home is the endpoint of its own unique combination of pipes and infrastructure, meaning detailed tap water composition can change depending on where you live. Add in potential contaminants that aren’t always tested for and regulations that sometimes fail to flag chemicals known to be harmful, it’s easy for consumers to feel in the dark about what they’re drinking in their own home. 

But even though a city’s water report doesn’t always present a full picture, every household has a surprising amount of control over what is in their water, from installing high-quality filters to gauging what comes out of their taps with water tests.

ROSE offers an at-home water test that screens for more than 100 contaminants, including seven PFAS compounds, through an ISO-certified lab, and pairs every result with fixes matched to what's actually in the water.

“Get your water tested. It's very, very important because you don't know. Your water could be perfectly fine, but it may not be, and knowledge is power,” Andrew said. 

What is the last mile problem?

Safety tests can’t feasibly cover every pipe and drop of water that connects directly to homes, so a lot of potential problems during the last stretch of water’s journey risk going unnoticed.

“There's that last mile, or the last few miles, where you could be introducing different things into the water,” says Agustin Pierri, technical director at WECK Labs, an analytical testing laboratory that tracks environmental contaminants.

One potential risk is having pipes that leach lead, a notoriously toxic metal. Globally, lead poisoning was responsible for around 3.5 million deaths in 2023, primarily due to cardiovascular issues tied to lead exposure, according to the Institute for Health Metrics & Evaluation’s most recent Global Burden of Disease study, published in 2025 in The Lancet. . Children, who consume more water relative to their body weight than adults, are even more vulnerable to lead exposure. A 2017 study, published in JAMA, tracked hundreds of people in New Zealand from the 1970s to the 2010s, and associated lead exposure as children with lower IQ scores over the course of their lives, as well as jobs that required less education and lower incomes compared to their parents.  

How do I know if my pipes were made with lead?

In the U.S., houses constructed before 1986 are more likely to have been built with lead piping, or pipes that were soldered with lead, Pierri said. In 2025, the EPA identified 4 million remaining lead service lines, pipes that connect main water lines to an individual home’s plumbing. 

While the threat of lead and other chemicals leaching into your water might not always show up in city water reports, there are other ways to know if your house is exposed. Testing tap water is the most sure-fire option, but you can also reach out to your water utility, or even manually check your house’s piping for lead using only a magnet and a penny.

Are my pipes up to date?

Most Americans’ drinking water needs rely on two million miles of underground pipes, operated by some 150,000 public water systems, according to the American Society of Civil Engineers’ 2025 infrastructure report card. The review reported aging transmission and distribution pipelines represent the most pressing challenge for more than half of these utilities. Almost 20% of installed water mains, accounting for around 450,000 miles of pipe, have likely exceeded their useful lives but have yet to be replaced, according to the report.

Age makes pipes more prone to leaking or breaking. A corroded metal pipe can leach harmful heavy metals including lead into your drinking water, according to a global 2026 literature review published in the journal Water. While tap water generally holds lower metal concentrations than surface or groundwater, the amounts identified exceed public health recommendations in many countries, which the authors largely attributed to aging pipelines, corrosion, and insufficient monitoring. 

What do water reports leave out?

You’ve tackled the last mile problem by checking for lead and making sure your pipes are up to date. Anything else that could contaminate your water should be identified and filtered out at the treatment facility, way before it reaches your home. Right?

Not necessarily. While utilities do test and clean water before it’s distributed to consumers, they don’t always catch everything. Take PFAS, a class of synthetic substances commonly known as “forever chemicals,” which have been linked to higher risk of some cancers, immune system issues, and developmental delays, according to the EPA. 

There are around 14,000 compounds considered PFAS, but only six are regulated in U.S. water. In May 2026, the Trump administration proposed rescinding regulations for all but two of those six compounds, while also delaying compliance deadlines. 

The EPA's regulatory process is generally reactive, according to Pierri, requiring a high bar of demonstrated harm, usually spanning several years, before a contaminant gets an enforceable limit. But that gap could let plenty of potentially harmful substances slip through guardrails, making home testing even more important.

“There are obligations for the utilities to test for different things that are known to be harmful or carcinogenic or otherwise not good to have in the water. But there are also classes of compounds that are not yet regulated that potentially could be an issue,” Pierri said.

Finding the right fix for you

Water reports can be useful resources, but between regulatory gaps, unknown chemicals, and aging pipelines, there’s really only one way to know for certain the water springing from your tap is the safest it can be. 

Testing your water is an essential first step to knowing what exactly is in it, according to Andrew, the water filtration expert. That composition can help narrow down which type of water filter might be the best choice for you and your household.

“Once you have knowledge and understanding of what you're dealing with, then you can start to take the steps to implementing a solution,” Andrew said.

FAQs

What is the "last mile" problem in tap water safety?

The last mile problem refers to the stretch of pipes between a municipal water distribution center and your home's kitchen tap. Even if water is properly treated at the facility, it can pick up contaminants, including lead and other heavy metals, as it travels through aging or corroded private pipes that aren't covered by standard municipal testing.

How do I know if my home has lead pipes?

Homes built before 1986 are most likely to have lead pipes or lead-soldered plumbing. You can check by contacting your water utility, manually inspecting your pipes using a magnet and penny (the EPA provides instructions), or testing your tap water directly. The EPA estimates 4 million lead service lines remain in use in the U.S. as of 2025.

Is tap water safe to drink?

Tap water goes through extensive treatment and testing before it reaches your home, but it isn't always free of harmful contaminants. Regulatory gaps, aging infrastructure, and unmonitored chemicals like PFAS mean municipal water reports don't always reflect everything in your water. Testing your home's tap water is the most reliable way to know what you're drinking.

What are PFAS and are they in tap water?

PFAS (per- and polyfluoroalkyl substances) are a class of synthetic "forever chemicals" linked to cancer, immune system issues, and developmental delays. There are around 14,000 PFAS compounds, but as of 2026, only two are federally regulated in U.S. drinking water. PFAS contamination in tap water is widespread across the U.S., with elevated concentrations commonly found near industrial sites, military bases, and airports.