01The verdict: is Green Valley water safe?
Green Valley's tap water meets most EPA standards but has areas that warrant attention. With a grade of B+ (84.1/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,275 residents using groundwater (wells).
2 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 0.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓2 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Green Valley's drinking water received a grade of B+ (84.1 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,275 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 4 violations on record, including 3 health-based violations. 2 remain unresolved.
Green Valley ranks #290 out of 690 cities in California for water quality, placing it mid-range in the state. Green Valley relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff. As a small community water system, Green Valley may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Green Valley's water
Every contaminant flagged in Green Valley, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in California
Cities ranked by compounds detected Cu Copper in California
Cities ranked by 90th-percentile copper
03Green Valley's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 4 violations on record, including 3 health-based violations. 2 remain unresolved.
9 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 10 ppb since 1993. Latest reading: 0 ppb (2025) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Green Valley's water comes from
Green Valley's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under local government ownership.
1,275 people
Residents served across Green Valley's service area.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals. Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds. The system is operated by local government ownership and serves approximately 1,275 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| GREEN VALLEY CWD | CA1910244 | 1,275 | Groundwater |
05Pressure on Green Valley's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Flood & storm history
10 federal disaster declarations on record for Los Angeles County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
06How Green Valley compares
Scores for nearby California cities on one line, with the average marked.
dashed line = California average (57/100)
Green Valley scores 84.1/100 — above the California average of 57/100. It outscores 8 of 10 nearby cities. Full California rankings →
42.8 / 100FSan Jose, CA
28 / 100BOakland, CA
77.9 / 100FSan Diego, CA
39.7 / 100FSacramento, CA
31.2 / 100ABurlingame, CA
89.2 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Green Valley's water — not generic advice.
A basic carbon filter still helps
Green Valley's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Green Valley alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Green Valley, CA tap water safe to drink?
Green Valley's water quality earned a grade of B+ (84.1/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #290 out of 690 cities tested in California.
What contaminants are in Green Valley's water?
Lead was measured at 0.0 ppb (90th percentile). 4 violations are on record.
How is Green Valley's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Green Valley?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Green Valley's water come from?
Green Valley's water is sourced from Groundwater. The city has 1 water system serving approximately 1,275 residents.
What health violations has Green Valley's water system had?
Green Valley has 3 health-based violations on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
Is Green Valley's groundwater at risk of contamination?
Green Valley uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 4 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Green Valley's water compare to other cities?
Green Valley ranks #290 out of 690 cities in California (better than 58% of state cities) and #6047 out of 15382 cities nationally (61th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Green Valley's small water system affect quality?
Green Valley's system serves approximately 1,275 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 4 violations on record.