EPA ID CA4310011 · checked 16 Oct 2026
San Jose tap water: what EPA testing found
San Jose Water (EPA record: SAN JOSE WATER) serves 1,039,920 people in CA from surface water.
What the data shows
PFAS found, below EPA’s limits (PFOS, PFHxS)
2 PFAS compounds reached EPA’s reporting level in at least one sample; no sampling point averaged above a limit.
What fits: Pick a filter whose listing certifies PFOA/PFOS (or total PFAS) reduction under NSF/ANSI 53 or 58. Under-sink reverse osmosis units and some carbon filters and pitchers carry it; the certification for the exact model is what counts, not the filter type.
Certified — IAPMO listing, checked 16 Oct 2026- 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
- APEC Water Tankless RO System 4 Stage Water Filter, 1000 GPD Reverse…Under-sink reverse osmosis · ROTL-A1000
- 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- Aquasana Clean Water MachineCountertop dispenser · AQ-CWM2-B · 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
- 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
- Waterdrop Instant Hot Water Dispenser, Reverse Osmosis System, K6Under-sink reverse osmosis · WD-K6-W · check NSF’s listing yourself
- Waterdrop X Series Reverse Osmosis System, X12Under-sink reverse osmosis · WD-X12 · check NSF’s listing yourself
- Aquasana HealthShield Whole House Water Filtration SystemWhole-house filter · WH-HS · check NSF’s listing yourself
NSF’s and WQA’s listings can’t be checked automatically; each product page also links to WQA’s.
Treatment-technique violation (turbidity or filtration)
1 health-based violation since 2016, the latest starting 2023-06-01.
What fits: These are treatment-technique rules for the plant (turbidity and filtration). The utility fixes them; follow its public notices, including any boil-water advisory.
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)
1,125 results from 19 sampling points, 15 Feb 2023 to 11 Feb 2025. 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 CA4310011). Limits: EPA PFAS rule.
| Contaminant | Detected in | Highest result | Average | EPA limit |
|---|---|---|---|---|
| PFOA | 0 of 37 | not detected | 0 ng/L | 4 ng/L |
| PFOS | 2 of 37 | 6.2 ng/L | 0.28 ng/L | 4 ng/L |
| PFHxS | 12 of 36 | 5.5 ng/L | 1.24 ng/L | 10 ng/L* |
| PFNA | 0 of 37 | not detected | 0 ng/L | 10 ng/L* |
| HFPO-DA | 0 of 37 | not detected | 0 ng/L | 10 ng/L* |
| Lithium | 5 of 41 | 10 µg/L | 1.15 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
| Period began | Contaminant or rule | Violation | Measured | Status |
|---|---|---|---|---|
| 1 Jun 2023 | Surface Water Treatment Rule | Treatment Technique (SWTR and GWR) | – | Returned to Compliance (16 Aug 2023) |
Source: EPA SDWIS via Envirofacts and the ECHO report for CA4310011, retrieved 16 Oct 2026.
Hardness
16.8 grains per gallon (highest plant or source figure of 3, 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 |
|---|---|---|
| Mountain surface water (Santa Cruz Mountains) | – | 8.83 |
| Groundwater (wells) | – | 16.8 (10.2–26.4) |
| Valley Water treated surface water (purchased) | – | 5.79 (4.5–8.54) |
From the same report. Which plant or source serves an address depends on where it is; the utility’s report explains its areas.
30 of this system’s ZIP codes are placed in a plant’s service area using the utility’s service-area map (checked 17 Oct 2026); the ZIP checker shows your ZIP code’s figure.
Places and ZIP codes served
San Jose, Los Gatos, Campbell, Cupertino, Santa Clara, Saratoga.
95008 95014 95030 95032 95033 95050 95070 95110 95111 95112 95113 95116 95117 95118 95120 95121 95122 95123 95124 95125 95126 95127 95128 95129 95130 95131 95132 95133 95136 95148
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.