Manassas, Virginia
Manassas Water Quality
City-owned lake water, soft and low in lead. The 2025 report's closest call is disinfection byproducts: trihalomethanes at 66.8 ppb against an 80 ppb limit.
TTHM 66.8 ppb (samples to 101) · HAA5 42.9 ppb · hardness 47 ppm · lead 90th percentile 0.5 ppb.
The short answer
Manassas treats water from Lake Manassas, its own reservoir on Broad Run. The 2025 report lists no violations. The result closest to its limit is trihalomethanes, at 66.8 ppb against 80 ppb, with individual samples up to 101 ppb.
The water is soft (47 ppm hardness) and lead was low (90th percentile 0.5 ppb). If you treat anything, carbon for byproducts is the match. A softener usually isn't.
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Tell us your Manassas address. We confirm coverage first, then schedule a licensed technician to test at your tap — no charge, no obligation.
What filtration does — and does not
Carbon and reverse osmosis solve different problems. Manassas's report points at carbon.
Where Manassas water comes from
A City-owned lake and plant, with a Potomac backup.
Lake Manassas
The City's own reservoir, an impoundment on Broad Run in western Prince William County with a 74.5-square-mile watershed.
Treated by the City
City of Manassas Utilities treats the lake water and disinfects it with chlorine. The report lists an average chlorine level of 2.66 ppm.
A Potomac backup
As a backup, the City can draw Prince William County Service Authority water treated at Fairfax Water's Corbalis plant on the Potomac.
What the 2025 Manassas report actually says
Results are from the City of Manassas 2025 Annual Water Quality Report. They are system-level figures, not a reading at your tap.
Trihalomethanes 66.8 ppb
The reported level against the 80 ppb limit, with individual samples from 12.1 to 101 ppb. The limit applies to a running average, and the report lists no violation.
Haloacetic acids 42.9 ppb
The reported level against the 60 ppb limit, with samples from 6.6 to 65.7 ppb. No violation.
Soft water: 47 ppm hardness
About 2.7 grains per gallon. Most homes on City water don't need a softener.
Lead low at the tap
In 2024 sampling, the 90th percentile was 0.5 ppb and none of 31 sites exceeded the action level. Copper was 0.0957 ppm, also with no exceedances.
Sodium 17.4 ppm
No federal limit applies. The report lists it for people watching sodium intake.
Fluoride 0.40 ppm
The level the report lists for 2025, well under the 4 ppm limit.
Manassas next to Alexandria and Fredericksburg
Alexandria buys Fairfax Water through Virginia American Water and uses chloramine, and its water is considerably harder. Fredericksburg gets most of its water from Spotsylvania County's Motts Run plant. Manassas runs its own lake and plant, so its report reflects one reservoir and one treatment process. For the City's electric side, see Manassas battery backup.
Where these figures come from
Everything on this page traces to the City of Manassas.
- City of Manassas — Annual Water Quality Report, 2025, PWS ID 6685100 (PDF) — source, treatment and the 2025 results table.
- City of Manassas — Water compliance — where the City posts its water quality reports.
Matching treatment to the finding
Manassas's report supports carbon for byproducts. It does not support a default equipment sale.
Carbon filtration for byproducts
Trihalomethanes and haloacetic acids form when chlorine meets organic matter from the lake. Carbon certified for them, at the tap or whole-house, reduces them along with chlorine taste.
Skip the softener
At 47 ppm, Manassas water is soft. A softener solves a problem most City customers don't have.
Check your service line
Lead results were low, but the City posts a service line inventory. Look up your address before assuming anything about older plumbing.
Test before buying anything
Byproduct levels vary by location and season. A test at your tap shows what reaches your kitchen.
How the free test works
A licensed technician tests at your kitchen tap, walks the plumbing, and tells you which of the findings above applies to your house and which does not. There is no charge and no obligation.
Seamless Home is the licensed contractor of record on the work that follows. Installation is performed by vetted installing partners engaged as our subcontractors, and the workmanship obligation stays with us. Coverage is confirmed per service area rather than promised as blanket availability.
What a water treatment job with us covers
Installation and replacement of whole-home and point-of-use treatment, specified against what your water actually contains.
Sediment filtration
Installation of the first stage that protects everything downstream of it, sized to the service line and the household draw.
Softening
Installation of ion-exchange softening where hardness is the problem, including the drain connection the plumbing code treats as indirect waste.
Carbon filtration
Installation of carbon stages for taste, odour and disinfection by-products, specified from your utility's own water quality report.
Reverse osmosis
Point-of-use installation at the kitchen sink where the target is dissolved solids rather than whole-home flow.
Disinfection
Installation of UV or equivalent treatment where the supply is a private well or is otherwise not continuously disinfected.
System replacement
Replacing equipment that has reached the end of its service life, including the discharge and air gap details an inspector looks at.
This is installation and replacement work, specified from a published water quality report or a test of your supply — not from a sales chart. Coverage is confirmed per service area rather than promised as blanket availability.
What the work actually looks like
Treatment equipment is plumbing. Most of the job is the connection, the drain and the code detail behind it.
Manassas water, answered plainly
Where does Manassas water come from?+
From Lake Manassas, the City's reservoir on Broad Run, treated by City of Manassas Utilities. The City can also draw Potomac River water from the Prince William County Service Authority as a backup.
Is Manassas water safe?+
The 2025 report lists no violations. The closest result to its limit is trihalomethanes: 66.8 ppb against 80 ppb, with some individual samples above 80 while the running average stayed compliant.
Is Manassas water hard?+
No. The report lists hardness at 47 ppm, about 2.7 grains per gallon, which is soft.
Is there lead in Manassas water?+
Lead comes from service lines and household plumbing, not the lake. In 2024 tap sampling the 90th percentile was 0.5 ppb, and none of 31 sites exceeded the 15 ppb action level.
Does this cover all of the Manassas area?+
No. This page covers City of Manassas Utilities customers. If your water bill comes from another utility, that utility's own annual report applies.
Where do these figures come from?+
The City of Manassas Annual Water Quality Report for 2025 (PWS ID 6685100). Third-party aggregators are not used.
Related resources
Home water purification and treatment
The national service page behind this one.
Learn more →Alexandria water quality
Fairfax Water via Virginia American Water, with chloramine.
Learn more →Fredericksburg water quality
Rappahannock River water from the Motts Run plant.
Learn more →Manassas battery backup
City-owned electric service, not Dominion Energy.
Learn more →All home services
Water, battery, HVAC and solar under one licensed contractor of record.
Learn more →Get a free test at your tap
A licensed technician tests at your kitchen tap and tells you which findings apply to your house — disinfection byproducts, lead or nothing at all. No charge, no obligation, and coverage confirmed at your address first.
Get a free test