Winston-Salem Water Quality Guide: Sources, Hardness, PFAS & Wells

Where does Winston-Salem's tap water come from?

The city utility draws from two surface water sources: the Yadkin River and Salem Lake. According to the utility's 2025 Water Quality Report, water is treated at three plants with a combined capacity of 91 million gallons per day.

• R.W. Neilson plant (48 MGD): Yadkin River. The utility notes a modernization project at this plant that began in late 2021.
• P.W. Swann plant (25 MGD): Yadkin River.
• Thomas plant (18 MGD): Salem Lake and the Yadkin River.

The utility serves Winston-Salem and Forsyth County, and its department page describes roughly 391,000 residential, business and industrial users and more than 2,300 miles of water mains. The system map in the annual report shows storage tanks labeled Kernersville, Clemmons, Lewisville, Walkertown and Tobaccoville, but the report does not spell out which towns or addresses are customers. If you live in one of those communities or in an unincorporated area such as Pfafftown or Rural Hall, check your water bill to see who your provider is.

How is Winston-Salem water treated and disinfected?

The 2025 report lists chlorine as the disinfectant, described as a water additive used to control microbes. It reports a distribution-system average of about 1.02 ppm, with a range of 0.02 to 1.98 ppm. The report does not mention chloramine.

Fluoride is added to promote strong teeth. The report lists an average of 0.70 ppm at the treatment plant, with a range of 0.53 to 0.83 ppm.

Disinfection byproducts

Chlorine can react with natural organic matter in river and lake water to form byproducts such as trihalomethanes (TTHM) and haloacetic acids (HAA5). The 2025 report lists a TTHM running average of 69.1 ppb against an 80 ppb limit, and a HAA5 average of 38.7 ppb against a 60 ppb limit, and states the system met all standards. Individual samples varied during the year, so if byproducts are your concern, read the table rather than the headline.

Earthy taste and smell

The report lists geosmin and 2-MIB, two compounds produced by algae in raw water. It describes them as causing an earthy or musty taste or odor, with no known negative health impacts, and notes they are not regulated. If your water tastes musty at certain times of year, this is a likely explanation, and it is also something a carbon filter commonly addresses.

How do you read the Winston-Salem Water Quality Report?

Federal rules require the utility to publish a Consumer Confidence Report each year. Here is a quick way to read it:

1. Open the utility's current report page: Water Quality Report 2025, or the shortcut cityofws.org/wqr2025. Older years are posted on the same site.
2. Find the regulated contaminants table. Compare the "highest level detected" or average to the legal limit (MCL) in the next column.
3. Check the disinfection byproducts rows (TTHM and HAA5) and the disinfectant row (chlorine).
4. Look at the PFAS rows. Note whether each compound was detected, and the range in parts per trillion (ppt).
5. Check the lead and copper section. The 90th percentile value and the number of sites above the action level are what matter.
6. Look at physical characteristics such as hardness, pH and alkalinity, which are not health standards but affect scale, taste and pipes.
7. Use the pipe-material map at cityofws.org/pipes to check what is known about the service line at your address.

For hardness, the utility reports a range of 9.0 to 28.0 ppm with a 17.5 ppm annual average. That is on the soft end of the scale, so most city-water households do not need a water softener for hardness reasons.

Is there PFAS in Winston-Salem drinking water?

The utility's 2025 report includes a PFAS table for treated water. It lists low-level detections of PFOS and shows most other PFAS it tested for as not detected, with the highest reported value (2.1 ppt) below EPA's 4.0 ppt limit for PFOS. The report itself references EPA's 4.0 ppt figure for PFOS and PFOA. Read the table directly for the compound-by-compound results, because that is the authoritative version.

On the federal side, EPA's PFAS drinking water page, last updated in May 2026, says the 2024 rule set 4.0 ppt limits for PFOA and PFOS and that EPA has proposed keeping those while allowing extra time, to 2031, to comply. EPA has also proposed rescinding the separate limits for PFHxS, PFNA, GenX (HFPO-DA) and the hazard index mixture. These are proposals, so the rules may change.

For more background, see our guide to PFAS in drinking water. It is written for Charlotte, but the explanation of the compounds and standards applies here too.

Why do some Winston-Salem homeowners still filter their water?

City water here is reported as compliant, so filtering is a preference for many households rather than a requirement. Common reasons in this market:

• Taste and odor: chlorine taste, and the seasonal earthy or musty taste linked to algae compounds.
• PFAS peace of mind: even low detections lead some households to add a certified filter.
• Older plumbing: homes built before the 1980s may have lead solder or older fixtures. The utility says household plumbing is the likely source of any lead at the tap.
• Private wells: iron, manganese, acidity and bacteria are common concerns (see below).
• Sensitive uses: some people filter for infant formula, immune-compromised family members, aquariums or coffee.

A whole-house system treats every tap, while a point-of-use filter treats only drinking water. Our comparison of a whole-house filter vs. a water softener explains why the two do different jobs, and do you need a whole-house water filter? walks through the decision.

What about lead pipes and service lines?

The utility reports that in its 2025 tap sampling the lead 90th percentile was not detected and no sites exceeded the 15 ppb action level, though individual results ranged up to 8.0 ppb. The report says treatment has been used to prevent lead leaching since 1992.

The utility has published an initial service line inventory. You can look up your address at cityofws.org/pipes. Lines marked "predicted lead" or "predicted non-lead" need to be photo-verified, and customers can self-report their private-side pipe material.

What should private well owners in Forsyth County know?

Not everyone in Forsyth County is on city water. Homes on wells, including many rural properties around Rural Hall, Pfafftown, Lewisville, Clemmons and Kernersville, are responsible for their own testing. Public utilities are tested and reported on; private wells are not.

The state's Forsyth County well data page summarizes results from wells that have been tested. It does not say how the wells were chosen, so treat the figures as a rough picture rather than a countywide rate. The page shows:

• Iron: above the 300 µg/L secondary (taste and staining) standard in 55 of 241 wells tested.
• Manganese: above the 50 µg/L secondary standard in 35 of 240 wells.
• Lead: above the 15 µg/L action level in 19 of 395 wells.
• pH: 50 wells fell below the 6.5 to 8.5 range, which can make water corrosive to plumbing.
• Arsenic: above the 10 µg/L standard in 2 of 241 wells.

Iron and manganese are secondary standards, meaning they affect taste, color and staining rather than being enforceable health limits. Low pH, lead and bacteria deserve more attention.

What does NC recommend testing?

The NC Division of Public Health well water FAQ recommends the following:

• Every year: total and fecal coliform bacteria, plus a wellhead inspection.
• Every two years: heavy metals, nitrates, nitrites, lead and copper.
• Every five years: pesticides and volatile organic compounds.
• After flooding, repairs, or a change in taste, color or odor: test again.
• New wells: test before drinking, within 30 days of completion.

Tests can go through the State Laboratory of Public Health, your local health department, or a state-certified commercial lab. Contact Forsyth County Environmental Health for current procedures and fees. For deeper treatment options, see our well water filtration guide, written for the Charlotte area but useful for Piedmont wells generally.

Winston-Salem-area situations: what should you do?

Use this list to match your home to a next step.

• If you are on city water and only dislike the taste: try a certified carbon filter (NSF/ANSI 42) at the kitchen tap or a pitcher before anything bigger.
• If you are on city water and want to reduce PFAS or lead: look for a point-of-use filter certified to NSF/ANSI 53 or 58 for those specific contaminants. EPA names these standards for PFAS reduction.
• If your home was built before the 1980s: check cityofws.org/pipes, look at your service line, and consider a lead test.
• If you are on a well and have never tested: start with bacteria, pH, lead, iron and manganese, then decide on treatment based on results.
• If your well water stains fixtures orange or black: that points to iron or manganese, and the right treatment depends on the form and level, so test first.
• If your well water has a low pH: neutralizing treatment may be discussed, and a copper and lead test is sensible.
• If you are unsure whether you are on city water or a well: look at your bill or call the utility at 336-727-8000.

When should you test your water?

• You have a private well (annually for bacteria at minimum).
• You notice a change in taste, smell or color.
• You have an infant, are pregnant, or someone in the home has a health condition.
• You have older plumbing or recently renovated.
• A flood, line break or repair has affected your supply.
• You received a notice from the utility about your service line.

City customers can compare the annual report to their own results. You can also request a free local water report as a starting point.

What should you ask a water treatment installer?

1. Which contaminant is this system meant to reduce, and what test result supports that?
2. Is the product certified to the relevant NSF/ANSI standard for that contaminant, and can I see the listing?
3. What are the maintenance schedule and annual replacement costs?
4. Will it change my water pressure or require a drain connection?
5. What happens if my results change later?
6. Is the quote itemized, and are test fees separate?

Costs vary widely by system type and home, so get more than one quote. Our whole-house filter cost guide explains what typically drives prices. Browse water treatment companies in Winston-Salem; directory listings are informational and are not endorsements.