What's in Charles County, MD tap water?
Charles County sits about 29 miles from our Arlington base and is served primarily by Town of La Plata, which provides water to roughly 11,500 people. It draws from the Potomac River watershed. Most of the DC metro area drinks treated Potomac River water. Because that surface water is heavily disinfected to stay safe across a long distribution system, the contaminants that most often exceed EWG's stricter health guidelines here are chlorination byproducts, alongside unregulated contaminants like PFAS and hexavalent chromium.
Find a local installerTown of La Plata water quality report, explained
What testing of Town of La Plata water shows for Charles County, compared with EWG's health guidelines. Being above a guideline is not a legal violation.
Primary water system (EPA)
Town of La Plata
Serves about 11,500 people
Contaminants EWG most often flags above its health guidelines for the Potomac River watershed:
Larger areas have more than one water system. Enter your exact zip code below for your utility's own EPA record and EWG report.
Measured by the EPA · Charles County, MD
Charles County, MD tap water is fully legal.
It is also 5× the health standard for lead.
Charles County draws its water from the ground rather than from a river, through a small system serving about 11,535 people. Well water arrives with whatever the rock it sat in put into it, and small systems test less often than large ones.
Groundwater does not carry the chlorination byproducts that dominate river supplies, because it needs far less disinfection. What it carries instead comes out of the rock: arsenic, radium, manganese, and nitrate where there is farming above the aquifer. Boiling concentrates all of them rather than removing them.
Every federal limit that applies here is met. Those limits weigh what removal costs. EWG says its health standards are “based only on protecting health and does not consider technical feasibility or the cost of water treatment”. Here is how far apart the two are.
Harm to the brain and nervous system · EPA limit 10 ppb (action level, lowered from 15 ppb, in force November 2027)
It was tested for 29 PFAS compounds in the EPA's latest round and none came back above reporting limits — genuinely good news, and a single window in time. Lead sampling put the ninetieth percentile at 1 ppb — meaning nine in ten homes tested below that, and one in ten above it. It has no violations on file.
Town of La Plata, on the EPA's record
- Source
- groundwater
- Connections served
- 4,723
- People served
- 11,535
How this water is treated before it reaches you
Treatment makes water safe to distribute. It is not designed to remove PFAS, and chlorine-based disinfection creates byproducts of its own.
Levels: EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR5, 2023–2025) for PFAS, and the Lead and Copper Rule 90th-percentile result for lead and copper — the highest reported for Town of La Plata. Health standards: EWG's published drinking water standards, updated February 2025. Levels vary by sampling point and date, and being above a health standard is not a legal violation.
11 contaminants above EWG's health guidelines
Everything EWG found above its guideline in Charles County's water, from testing in 2013-2024. A level can be under the legal limit and still be listed here: EWG's guidelines are set to protect health, not to be easy to meet.
| Contaminant | In this water | EWG guideline | Times over |
|---|---|---|---|
| Bromochloroacetic acid | 4.83 ppb | 0.02 ppb | 242× |
| Haloacetic acids (HAA9) | 12.6 ppb | 0.06 ppb | 209× |
| Total trihalomethanes (TTHMs) | 16.6 ppb | 0.15 ppb | 111× |
| Haloacetic acids (HAA5) | 7.18 ppb | 0.1 ppb | 72× |
| Arsenic | 0.205 ppb | 0.004 ppb | 51× |
| Radium, combined (-226 and -228) | 1.11 pCi/L | 0.05 pCi/L | 22× |
| Dibromochloromethane | 1.81 ppb | 0.1 ppb | 18× |
| Bromodichloromethane | 0.780 ppb | 0.06 ppb | 13× |
| Nitrate | 1.06 ppm | 0.14 ppm | 7.6× |
| Chromium (hexavalent) | 0.108 ppb | 0.02 ppb | 5.4× |
| Chloroform | 1.63 ppb | 0.4 ppb | 4.1× |
Source: EWG Tap Water Database, Waldorf (Charles County DPW) (MD0080049).
The fix for Charles County water
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Common in U.S. tap water
Charles County water quality FAQ
Is Charles County, MD tap water safe to drink?
Public water in Charles County meets federal EPA legal limits. But "legal" is not the same as "clean": across the Potomac River watershed, independent testing routinely finds contaminants like total trihalomethanes (TTHMs) and haloacetic acids (HAA5) above EWG's stricter health guidelines. Enter your zip code above to see your exact utility's record.
What contaminants are common in Charles County water?
For the Potomac River watershed, the contaminants that most often exceed health guidelines are total trihalomethanes (TTHMs), haloacetic acids (HAA5), hexavalent chromium (chromium-6), PFAS (forever chemicals) and lead (from older service lines). Your specific levels depend on your utility, which you can look up by zip code above.
Does Sanavia install reverse osmosis systems in Charles County?
Yes. Charles County is roughly 29 miles from our Arlington base and inside our service area. A Sanavia Hydra reverse osmosis system installs under your sink and reduces every contaminant class above, and we'll mail you a free water test kit.
Where does Charles County tap water come from?
Charles County's primary public water system is Town of La Plata, which serves roughly 11,500 people. It sits in the Potomac River watershed, so its water shares that region's contaminant profile. Larger areas may have more than one utility, so enter your exact zip code above for your own system's EPA record.
Is well water in Charles County tested for these contaminants?
No. Private wells are not covered by municipal testing, so the responsibility falls on the homeowner. If your Charles County home is on a well, nitrate and naturally occurring contaminants are worth testing for specifically, and a reverse osmosis system reduces them at the tap. We'll mail you a free water test kit either way.
Contaminants common in the Potomac River watershed
Each of these is a plain-English guide to a contaminant class common in Charles County and the surrounding Potomac River watershed — what it is, the health context, and what actually removes it.
Reverse osmosis in La Plata & Charles County, MD
Town of La Plata treats this water to the federal standard, yet the contaminants listed above still exceed EWG’s stricter health guidelines — Total trihalomethanes (TTHMs), Haloacetic acids (HAA5), Hexavalent chromium (chromium-6) and 2 more. Most of them either pass straight through treatment or form after the plant, in the pipes between it and the tap, which is why the fix has to be at the tap as well.
Lead is the one nothing upstream can fix. It does not arrive from the treatment plant; it comes off the service line and the household plumbing in between, which is why two houses on the same street test differently. A reverse osmosis membrane sits at the end of that run, after every pipe the water has already passed through.
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Full testing record for Charles County · Find a local installer
Detailed city water reports
For the largest DC-metro utilities we publish the full measured contaminant table.
Nearby areas we serve
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