EPA ID CA3710020 · checked 16 Oct 2026
San Diego tap water: what EPA testing found
City of San Diego (EPA record: SAN DIEGO, CITY OF) serves 1,408,937 people in CA from surface water.
What the data shows
Lithium above EPA’s screening level (there is no legal limit)
Highest result 65 µg/L; EPA’s health reference level for screening is 10 µg/L.
What fits: EPA has no lithium limit, and no NSF/ANSI standard has a lithium reduction claim, so no home filter is certified for lithium.
Lead from home plumbing (not in this data)
UCMR 5 does not test for lead, and lead usually enters water from service lines and plumbing inside buildings. Your utility’s lead service line inventory says whether your address is served by a lead line.
What fits: Lead comes from lead service lines, solder and fixtures inside buildings, not usually from the treatment plant. Use a filter certified for lead reduction (NSF/ANSI 53 or 58) at the tap you drink from.
Certified — IAPMO listing, checked 16 Oct 2026- Brita Elite Replacement Filter, formerly Longlast+Pitcher filter · OB06
- Culligan with ZeroWater Technology 10 Cup PitcherPitcher filter · ZEROP10
- PUR PLUS Lead Reducing Pitcher & Dispenser Replacement FilterPitcher filter · PPF951K
- ZeroWater 5-Stage Replacement FilterPitcher filter · ZR-017
- Culligan Scout 2.25 Gallon Gravity Countertop System with MaxClear…Countertop dispenser · MCSP
- PUR Faucet Filtration System, VerticalFaucet-mount filter · FM-3333B
- PUR PLUS Faucet Filtration System – Horizontal, ChromeFaucet-mount filter · PFM400H
- AquaTru Classic Countertop Reverse Osmosis Water PurifierCountertop reverse osmosis · AT2000
- Aquasana Claryum Direct Connect Under Sink Water FilterUnder-sink filter · AQ-MF-1
- Culligan EZ-Change Under Sink Drinking Water Filtration SystemUnder-sink filter · US-EZ-4
- Waterdrop 800 GPD Tankless Reverse Osmosis System - Waterdrop G3P800Under-sink reverse osmosis · WD-G3P800
- Waterdrop G3P600 Reverse Osmosis System - Waterdrop G3P600Under-sink reverse osmosis · WD-G3P600
Brand says certified — not found in IAPMO’s listing; check NSF- LifeStraw Home 7-Cup Glass Water Filter PitcherPitcher filter · LSH7SPC101 · check NSF’s listing yourself
- Aquasana Clean Water MachineCountertop dispenser · AQ-CWM2-B · check NSF’s listing yourself
- Brita Elite Advanced Water Filter Faucet System with Brita…Faucet-mount filter · FF-100 · check NSF’s listing yourself
- Brita Hub Countertop Water Filter System with Brita Hub FilterCountertop filter · 87340 · check NSF’s listing yourself
- Aquasana Claryum 2-Stage Under Sink Water FilterUnder-sink filter · AQ-6200 · check NSF’s listing yourself
- Aquasana Claryum 3-Stage Max Flow Under Sink Water FilterUnder-sink filter · AQ-6300M · check NSF’s listing yourself
- Aquasana Claryum 3-Stage Under Sink Water FilterUnder-sink filter · AQ-6300 · check NSF’s listing yourself
- A. O. Smith High Efficiency Reverse Osmosis SystemUnder-sink reverse osmosis · AOS-HERO-CHR · check NSF’s listing yourself
- APEC Water Tankless RO System 4 Stage Water Filter, 1000 GPD Reverse…Under-sink reverse osmosis · ROTL-A1000 · check NSF’s listing yourself
- APEC Water Ultimate 5-Stage 90 GPD High Output Reverse Osmosis Water…Under-sink reverse osmosis · RO-90 · check NSF’s listing yourself
- Aquasana SmartFlow Reverse Osmosis Water FilterUnder-sink reverse osmosis · AQ-SFRO2 · check NSF’s listing yourself
- Culligan Aquasential Smart Reverse Osmosis Drinking Water…Under-sink reverse osmosis · Aquasential Smart RO · check NSF’s listing yourself
- iSpring RCC7AK, NSF Certified 75 GPD, Alkaline 6-Stage Reverse…Under-sink reverse osmosis · RCC7AK · check NSF’s listing yourself
- Waterdrop X Series Reverse Osmosis System, X12Under-sink reverse osmosis · WD-X12 · check NSF’s listing yourself
NSF’s and WQA’s listings can’t be checked automatically; each product page also links to WQA’s.
PFAS and lithium (EPA UCMR 5)
480 results from 4 sampling points, 25 Jan 2023 to 7 Dec 2023. Averages count results below EPA’s reporting level as zero, as the PFAS rule does. Every number links to EPA’s UCMR 5 Data Finder (search PWSID CA3710020). Limits: EPA PFAS rule.
| Contaminant | Detected in | Highest result | Average | EPA limit |
|---|---|---|---|---|
| PFOA | 0 of 16 | not detected | 0 ng/L | 4 ng/L |
| PFOS | 0 of 16 | not detected | 0 ng/L | 4 ng/L |
| PFHxS | 0 of 16 | not detected | 0 ng/L | 10 ng/L* |
| PFNA | 0 of 16 | not detected | 0 ng/L | 10 ng/L* |
| HFPO-DA | 0 of 16 | not detected | 0 ng/L | 10 ng/L* |
| Lithium | 15 of 16 | 65 µg/L | 34.1 µg/L | none (screening level 10 µg/L) |
* PFHxS, PFNA and HFPO-DA limits (and the PFAS hazard index) are in the rule, but EPA proposed on 20 May 2026 to rescind them; not final as of 16 Oct 2026. UCMR 5 results are screening data, not compliance results: compliance uses quarterly running averages from 2029. Source file: EPA UCMR 5 occurrence data (dated 15 Oct 2026).
Health-based violations since 2016
None in EPA’s SDWIS data.
Source: EPA SDWIS via Envirofacts and the ECHO report for CA3710020, retrieved 16 Oct 2026.
Hardness
14.2 grains per gallon (highest plant or source figure of 4, 2025; varies by area), from the utility’s water report checked 16 Oct 2026. Size a softener for this water.
| Plant, source or area | Serves | Grains per gallon |
|---|---|---|
| Alvarado Water Treatment Plant | – | 13.9 (11.9–15.8) |
| Miramar Water Treatment Plant | – | 14.2 (11.7–16.7) |
| Otay Water Treatment Plant | – | 14.2 (11.8–15.8) |
| Purchased treated water | – | 8.48 (3.18–13.6) |
From the same report. Which plant or source serves an address depends on where it is; the utility’s report explains its areas.
Places and ZIP codes served
San Diego, Chula Vista, El Cajon, Escondido, La Jolla, La Mesa, Bonita, Carlsbad, Del Mar, Imperial Beach, Lakeside, Lemon Grove, National City, Poway, Ramona, Rancho Santa Fe, San Ysidro, Santee, Solana Beach, Spring Valley.
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ZIP codes the system reported to EPA for UCMR 5; place names from GeoNames (CC BY 4.0). A ZIP code can be split between systems.