about this page

We monitor water quality at every step to ensure safety when it gets to you.

This is a quick-read guide to many of the test results we share in our annual Drinking Water Quality Report.

PWD's 2019 Drinking Water Quality Report

If you like what you see here and want more details and science, check out our latest full report!

Part 1

Locally sourced,
locally made

We test here

Part 2

Safe transit through
the system

…and here…

Part 3
At home

The final stretch
to your tap

…and here.

Throughout this page, look for Lab Notes…

These notes explain how we test, and what the results mean for you.


photo of the intake at the Baxter Drinking Water Treatment Plant, taken from some elevation, looking out at an angle across the intake basin and the river, with a bit of New Jersey visible on the other side. The intake looks like a long swimming pool built right next to the river, with a narrow, straight barrier separating it from the rest of the river.
Intake from the Delaware River at one of our treatment plants in northeast Philadelphia.
Locally sourced, locally made

The experts working in our treatment plants take pride in using water drawn from our local rivers.

a close up of a scientist's hands in violet nitrile gloves holding a vial of water on a handheld testing device.

Testing quality at treatment plants

Once collected, river water goes through multiple processes, including settling, disinfection, and filtering. We ensure it’s crystal clear and safe.

We test it again once more to make sure the water will stay safe on its way to your tap.

What water treatment plant serves your area of the city?

a simplified map of Philadelphia shows the Schuylkill and Delaware rivers, with Market and Broad Streets indicated for reference. PWD's three drinking water treatment plants are displayed - Belmont on the northern edge of West Philly, Queen Lane on the other side of the Schuylkill in the northwest, and Baxter up in the Northeast by the Delaware.  Areas of the city are shaded in different colors and patterns to indicate which plant(s) provide water to those sections - Belmont is the primary source for the part of Philadelphia west of the Schuylkill - most of that area also recieves a mix of water from the other plants, with only a strip in the northern part of West Philly being served exclusively by the Belmont plant. Queen Lane serves Northwest Philadelphia, and Baxter serves all of the North and Northeast. Those areas meet around north Broad Street, with sections around and slightly west of Broad, and much of Center City and all of South Philly receiving a mix of water from Queen Lane and Baxter.
key indicating what the colors/patterns of shading in the map mean (map's alt text provides a detailed description)

Final Ingredients

Chlorine + Ammonia

Chlorine protects us from disease-causing organisms found in natural water. Ammonia is added to make chlorine last longer and reduce the bleach-like smell.


We adjust natural levels to help protect children’s teeth.

Zinc orthophosphate

Coats pipes to prevent corroding (or breaking down) over time.

illustration of a pipe with very little buildup on the inside, so water can flow through it easily and remain clean and clear
With corrosion control
pipe shown with corrosion and residue built up on the inside, impeding the flow, and particles that have broken loose are visible in the water.
Without corrosion control

Photo of a scientist in a lab, wearing a labcoat, blue nitrile gloves, and safety goggles, holding a sample vial of water. Lab equipment is visible but blurry in the nearer foreground and background. She is smiling as she examines the vial.
A PWD Environmental Scientist conducts testing on drinking water samples for clarity.

Before it leaves the plant

Consistent Quality

We constantly test our treated water for about 100 regulated contaminants, ranging from organisms like bacteria to chemicals like nitrate. No tests in 2019 found levels considered violations under state and federal regulations.

A Closer Look: Hardness

The hardness of water is determined by the minerals naturally dissolved in it. Hardness can vary based on natural conditions. For example, during a drought the hardness of water increases as the calcium carbonates in the natural waters become more concentrated.

A bar chart with calcium carbonates in parts per million indicated on the vertical scale, from 0 ("Soft") to 200 ("Very Hard"). Three bars on the chart indicate the hardness as tested at each of PWDs three drinking water treatment plants. Belmont is indicated at about 130 ppm, and Queen Lane about 150 ppm, both in the range considered "Hard". The bar for Baxter indicates a bit under 100 ppm, considered "Moderately Hard".
☑ Result:

Philadelphia’s water is moderately hard or hard, depending on which treatment plant serves your neighborhood.

Hardness matters if you use water for activities like brewing or aquariums.

Most customers don’t need to treat their water for hardness.


Safe transit through the system

We have about 3,100 miles of water mains that deliver clean tap to customers. To ensure water stays safe as it moves from the plant to you, we take samples and use online monitoring to track real-time water quality data, 24/7.

photo of a man filling a glass bottle from a monitoring tap in a utility box mounted on a cinderblock wall.
A tap used to test water at one of dozens of sites throughout Philadelphia.

A Closer Look: Residual Chlorine

This test is done throughout the system. It checks that the chlorine added at plants is still at levels that keep water fresh and safe while staying within regulations.

A chart showing the range of acceptable levels of Residual Chlorine in parts per million (ppm). The lowest level allowed is indicated at 0.2 ppm, while the highest level allowed is indicated at 4.0 ppm. PWD's monthly average is shown to be right in the middle, staying within 0.2 ppm of 2.0 ppm.

Better than standards

We travel the city to collect samples of drinking water from fire and police stations, pumping stations, and more.

We do over 420 of these tests per month!

at home

The final stretch to your tap

Once it leaves our water main and enters your service line, there are things you can do to keep your water safe.

a cutaway diagram showing the basement of a home and the pipes underground outside it. a larger pipe running under the street is labeled "water main" and a pipe running from the main into the basement of the home to the water meter is labeled "your service line"

Your Plumbing

The water we send to you does not contain lead. But lead may be found in a customer’s service line, or in other home plumbing.

Replacing Service Lines

If you have a service line made of lead, we want to help! See the next section…

Healthy Home Habit

If you haven’t used water for 6 hours or more: Run your cold water for 3-5 minutes. This will flush out water that’s been sitting in your pipes.

It only costs a penny or two to ensure top-quality tap!

A Closer Look: Carefully Monitoring Lead

In addition to regular tests in customer homes, every three years we complete a rigorous round of sampling for lead and copper. We share the results with the EPA and the public.

The EPA requires that 90% of homes with lead service lines sampled show lead levels less than 15 ppb.

A chart showing lead levels detected in sampling from homes with lead service lines, measured in parts per billion. Four rounds of PWD sampling results are all well below limits. The points indicated are under 6 ppb in 2011, around 5 ppb in 2014, 2 ppb in 2017, and about 3 ppb in 2019. The highest level allowed is indicated at 15 parts per billion.
Data based on samples from homes with lead service lines.

Lead levels are consistently lower than limits set by the EPA.

Soon, the EPA will update their guidelines for sampling. This will impact future results. We support this effort to make sure sampling is accurate, and to help identify homes with lead plumbing.

frequently asked questions

Why do water utilities add fluoride to water?

illustration of a tooth on a dark blue circle with a little sparkle

It’s a natural element that helps prevent cavities. Philadelphia’s Health Department (and dentists) recommend we add fluoride to a level that helps protect children’s teeth.

How hard is Philadelphia’s water?

Philadelphia’s water is considered moderately hard. Hardness depends on the treatment plant that serves your area of the city. See A Closer Look: Hardness.

Why does my tap water smell like a pool sometimes?

illustration of a nose with little dots near the nostrils to represent scent

The smell of chlorine means your water is safe and treated to remove harmful organisms. You can reduce the smell by keeping a pitcher of fresh water in the refrigerator. This also reduces the earthy odor, sometimes produced by algae in the rivers during spring.

What are PFAS?

Per- and polyfluoroalkyl substances (PFAS) are human made chemicals that have been used in industry and many consumer products. Initial research suggests some PFAS have been tentatively linked to health problems.

PWD is proactively testing for PFAS

In 2019, we began voluntarily testing for PFAS in the city’s rivers and creeks. PWD’s water sampling has not detected amounts at or above the EPA’s health advisory level of 70 ppt (parts per trillion) for PFOA and PFOS combined. A recent independent test by the Pennsylvania Department of Environmental Protection showed no detectable PFAS concentrations in Philadelphia’s treated drinking water.

Can I replace a lead service line?

Yes. If you don’t want to contact a plumber directly, apply for our Homeowners Emergency Loan Program (HELP). A zero-interest loan can cover the cost of replacement.

Learn more & apply

Also: PWD will replace lead service lines for free if they are discovered during planned work on water mains.

How do I get my water tested?

We offer free lead and copper tests for residential customers who have concerns about their water.

Call (215) 685-6300 to request an appointment.

Colder tastes better!

Water’s flavor is improved by colder temperatures.

Keep a covered pitcher in the fridge!

Photography: Calo Lopez Rosa, JPG Photo & Video