01The verdict: is Palomar Mountain water safe?
Palomar Mountain's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (93.4/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 4,416 residents using groundwater (wells).
1 unresolved violation on record
EPA records show an open compliance item 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 ↓Palomar Mountain's drinking water received a grade of A (93.4 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 4,416 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 16 violations on record, including 1 health-based violation. 1 remains unresolved.
Palomar Mountain ranks #71 out of 690 cities in California for water quality, placing it above average in the state. Palomar Mountain 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.
02What's in Palomar Mountain's water
Every contaminant flagged in Palomar Mountain, 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
03Palomar Mountain'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 16 violations on record, including 1 health-based violation. 1 remains 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 0 ppb since 2014. Latest reading: 0 ppb (2023) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Palomar Mountain's water comes from
Palomar Mountain'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 state ownership.
4,416 people
Residents served across Palomar Mountain'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 state ownership and serves approximately 4,416 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| PALOMAR OBSERVATORY | CA3702236 | 4,416 | Groundwater |
Water bodies near Palomar Mountain
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on Palomar Mountain'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 San Diego County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
06How Palomar Mountain compares
Scores for nearby California cities on one line, with the average marked.
dashed line = California average (57/100)
Palomar Mountain scores 93.4/100 — above the California average of 57/100. It outscores 10 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 Palomar Mountain's water — not generic advice.
A basic carbon filter still helps
Palomar Mountain'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 Palomar Mountain 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 Palomar Mountain, CA tap water safe to drink?
Palomar Mountain's water quality earned a grade of A (93.4/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #71 out of 690 cities tested in California.
What contaminants are in Palomar Mountain's water?
Lead was measured at 0.0 ppb (90th percentile). 16 violations are on record.
How is Palomar Mountain'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 Palomar Mountain?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Palomar Mountain's water come from?
Palomar Mountain's water is sourced from Groundwater. The city has 1 water system serving approximately 4,416 residents.
What health violations has Palomar Mountain's water system had?
Palomar Mountain has 1 health-based violation on record. The most recent violation was recorded in November 2022. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
Is Palomar Mountain's groundwater at risk of contamination?
Palomar Mountain 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 16 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 Palomar Mountain's water compare to other cities?
Palomar Mountain ranks #71 out of 690 cities in California (better than 90% of state cities) and #838 out of 15382 cities nationally (95th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.