Loading water data...
Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
EPA records for MODESTO, CITY OF • Updated September 2026
Grade D — based on EPA compliance records, lead testing and PFAS monitoring
MODESTO, CITY OF has notable problems in EPA's records — health-based violations, elevated lead or PFAS above the federal limit. A certified filter is a reasonable precaution.
Modesto, CA tap water is legal to drink but grades D on EPA's records, mainly because of PFOA or PFOS measured at or above the 4 ppt federal limit in 2023–2025 EPA sampling and lead at 12 ppb (90th percentile) — under the 15 ppb action level but above 5 ppb. A certified filter matched to those findings is a reasonable precaution.
Modesto, CA tap water is legal to drink but grades D on EPA's records, mainly because of PFOA or PFOS measured at or above the 4 ppt federal limit in 2023–2025 EPA sampling and lead at 12 ppb (90th percentile) — under the 15 ppb action level but above 5 ppb. A certified filter matched to those findings is a reasonable precaution.
MODESTO, CITY OF's most recent Lead and Copper Rule result (2025-01-01 to 2027-12-31) was 12 ppb at the 90th percentile, below EPA's 15 ppb action level. Because lead usually comes from service lines and household plumbing, homes built before 1986 should still test at the tap.
Yes. EPA's UCMR5 sampling (2023-11-16 to 2024-09-12) detected PFBS, PFHpA, PFHxA, PFHxS, PFOA, PFOS, PFPeA, with PFOA or PFOS at or above the 4 ppt federal MCL. Reverse osmosis and certified activated-carbon filters reduce PFAS.
No. EPA's SDWIS shows no violations of any kind for MODESTO, CITY OF since 2016.
MODESTO, CITY OF reports purchased surface water as its primary source and serves about 218,771 people (EPA PWSID CA5010010).
We recommend one. Reverse osmosis or a PFAS-certified carbon filter addresses the PFAS result. An NSF/ANSI 53 lead-certified filter addresses lead.
Compare filter options for your Modesto tap water
PFOA or PFOS was measured at or above EPA's 4 ppt limit in Modesto's UCMR5 sampling.
Unsure which contaminants to treat? Compare home kits and certified lab testing before buying.
Amazon. We may earn a commission, at no extra cost to you.
MODESTO, CITY OF · SDWIS records since 2016 · 5-year window starts 2021-09-13
EPA records no health-based violations for this system in the last five years.
No violations of any kind on file since 2016.
Source: ECHO SDWA bulk download (SDWA_VIOLATIONS_ENFORCEMENT.csv, SDWIS 2026Q2, file dated 2026-07-09, fetched 2026-09-13)
EPA Lead and Copper Rule 90th-percentile results reported by MODESTO, CITY OF
Below the action level, but detectable. In the most recent monitoring period on file (2025-01-01 to 2027-12-31), 90% of the homes MODESTO, CITY OF sampled had lead at or below 12 ppb.
EPA's action level is 15 ppb (dropping to 10 ppb under the 2024 Lead and Copper Rule Improvements). There is no safe level of lead; the 90th-percentile figure describes the system, not your tap — homes with lead service lines or pre-1986 plumbing can be higher.
| Monitoring period | Lead 90th percentile | vs 15 ppb action level |
|---|---|---|
| 2025-01-01 → 2027-12-31 | 12 ppb | Below the action level, but detectable |
| 2022-01-01 → 2024-12-31 | 0 ppb | Well below the 15 ppb action level |
| 2021-01-01 → 2023-12-31 | 0 ppb | Well below the 15 ppb action level |
| 2019-01-01 → 2021-12-31 | 0 ppb | Well below the 15 ppb action level |
| 2016-01-01 → 2018-12-31 | 0 ppb | Well below the 15 ppb action level |
| 2013-01-01 → 2015-12-31 | 0 ppb | Well below the 15 ppb action level |
| 2010-01-01 → 2012-12-31 | 0 ppb | Well below the 15 ppb action level |
| 2007-01-01 → 2009-12-31 | 2.5 ppb | Well below the 15 ppb action level |
| 2006-01-01 → 2006-12-31 | 1.2 ppb | Well below the 15 ppb action level |
| 2005-01-01 → 2005-12-31 | 2.5 ppb | Well below the 15 ppb action level |
| 2003-01-01 → 2005-12-31 | 2.5 ppb | Well below the 15 ppb action level |
| 2003-01-01 → 2003-12-31 | 2.5 ppb | Well below the 15 ppb action level |
Source: ECHO SDWA bulk download (SDWA_LCR_SAMPLES.csv, SDWIS 2026Q2, file dated 2026-07-09, fetched 2026-09-13)
EPA UCMR5 monitoring, 2023-11-16 to 2024-09-12 · 2,494 PFAS results at entry points to the distribution system
PFOA and PFOS measured at or above EPA's legal limit in at least one sample. Utilities have until 2029 (2031 under EPA's proposed extension) to comply with the 2024 PFAS rule, so a result above the MCL today is not yet a violation — but it is the number that matters for your health.
| Compound | Detects / samples | Max (ppt) | Reporting limit | EPA MCL |
|---|---|---|---|---|
| PFOA | 8 / 86 | 8.6 | 4 ppt | 4 ppt |
| PFOS | 15 / 86 | 26 | 4 ppt | 4 ppt |
| PFHxS | 13 / 86 | 9.3 | 3 ppt | 10 ppt |
| PFNA | 0 / 86 | < 4 | 4 ppt | 10 ppt |
| HFPO-DA | 0 / 86 | < 5 | 5 ppt | 10 ppt |
| PFBS | 2 / 86 | 4.3 | 3 ppt | hazard index only |
| PFHpA | 1 / 86 | 3.6 | 3 ppt | hazard index only |
| PFHxA | 8 / 86 | 6.1 | 3 ppt | hazard index only |
| PFPeA | 8 / 86 | 6.7 | 3 ppt | hazard index only |
“< 4 ppt” means below the laboratory reporting limit, not zero. ppt = parts per trillion (ng/L). Results are for finished water leaving the treatment plant.
Lithium (also monitored under UCMR5, not a PFAS): detected in 13 of 86 samples, max 21 µg/L. There is no federal limit for lithium.
What PFAS are and how to remove them → · Best filters for PFAS →
Source: UCMR5 occurrence data, EPA Data Summary July 2026 (UCMR5_All.txt)
EPA Six-Year Review 4 compliance samples for MODESTO, CITY OF · finished water only · dated data, released 2024
These are the regulated-contaminant samples MODESTO, CITY OF reported to its state between 2012 and 2019 — the most recent nationwide sample-level dataset EPA has published. Nitrate (as N), Total trihalomethanes (TTHM), Haloacetic acids (HAA5) are flagged below; the status column explains why. Treat this as history, not today's tap water.
| Contaminant | Samples | Average | Max | EPA limit | Status |
|---|---|---|---|---|---|
| Arsenic | 1,358410 detects | 0.881 µg/L | 8.6 µg/L | 10 µg/LMCL | Within MCL |
| Nitrate (as N) | 3,9993923 detects | 4.751 mg/L | 10.3 mg/L | 10 mg/LMCL | 1 of 3999 samples over MCL |
| Fluoride | 20 detects | 0 mg/L | ND | 4 mg/LMCL | Not detected |
| Chromium (total) | 21 detects | 3.2 µg/L | 6.4 µg/L | 100 µg/LMCL | Within MCL |
| Uranium (combined) | 1,8311719 detects | 8.773 µg/L | 28.31 µg/L | 30 µg/LMCL | Within MCL |
| Total trihalomethanes (TTHM) | 430276 detects | 24.486 µg/L | 98.16 µg/L | 80 µg/LMCL (LRAA) | 4 single samples over MCL; average within limit |
| Haloacetic acids (HAA5) | 249236 detects | 24.451 µg/L | 61.1 µg/L | 60 µg/LMCL (LRAA) | 1 single sample over MCL; average within limit |
| Lead (tap samples) | 20 detects | 0 µg/L | ND | 15 µg/Laction level (90th percentile) | Reported, not scored (compliance is on the 90th percentile) |
| Copper (tap samples) | 20 detects | 0 µg/L | ND | 1300 µg/Laction level (90th percentile) | Reported, not scored (compliance is on the 90th percentile) |
Averages count non-detects as zero. TTHM and HAA5 limits are locational running annual averages, so a single high sample is not a violation — we grade those on the average only. Lead and copper rows are individual tap samples and are shown for context; compliance (and our score) uses the 90th-percentile result above. LRAA = locational running annual average; ND = not detected.
Source: SYR4 Six-Year Review compliance monitoring data 2012–2019 (released 2024-03)
A point-of-use (under-sink) system typically runs $200-$600 installed; whole-house treatment $1,000-$3,000+ depending on flow and what has to come out. Tell us where you are and a certified water-treatment installer serving Modesto will follow up - no obligation.
MODESTO, CITY OF · 70,382 service lines inventoried · Q2 2026 snapshot
MODESTO, CITY OF reports no lead or galvanized-requiring-replacement service lines and has classified 100% of its 70,382 lines as non-lead. Lead can still come from pre-1986 plumbing and fixtures inside a home.
Source: EPA SDWIS Service Line Inventory (Q2 2026) · PWS ID CA5010010 · See all California lead service lines. We may earn a commission from filters and test kits, at no extra cost to you.
Surface-water systems draw from rivers, lakes or reservoirs and must filter and disinfect, which is why disinfection byproducts (TTHM, HAA5) are the readings to watch.
How to test your tap water and the treatment options that actually fit Modesto homes
The most reliable way to know what is actually coming out of your tap is a certified mail-in lab test. City-wide EPA data (like the report above) reflects the water leaving the treatment plant, but contaminants such as lead and copper can be picked up from your own service line and household plumbing — so the water at your Modesto faucet can differ from the system average. A state-certified lab measures dozens of contaminants at once with results you can trust; you can also find one near you through the EPA's certified-lab list at epa.gov/dwlabcert. Hardware-store test strips are cheaper and instant, but they only screen for a few basics (chlorine, hardness, pH, and a rough lead pass/fail) and are far less accurate — treat them as a first look, not a diagnosis.
Match the treatment to what your test finds. Reverse osmosis (RO) removes the widest range of contaminants — lead, arsenic, nitrate, PFAS, and dissolved solids — which makes an under-sink reverse osmosis system the most thorough choice for Modesto households with heavy-metal or PFAS concerns. If your main issue is taste, odor, or chlorine, an activated carbon filter (pitcher, faucet, or under-sink) is simpler and cheaper and handles chlorine and many organic compounds well, though carbon alone does not remove arsenic, nitrate, or most PFAS. NSF-certified pitchers rated for lead reduction are the easiest way to start today while you decide on a permanent setup.
We may earn a commission from testing kits and filters purchased through these links, at no extra cost to you.
What Modesto residents measured at their own tap (ZIPs 95313, 95350, 95351, 95354 +4 more). All reader results →
Reader submissions are unverified and shown separately from EPA data. They reflect one tap on one day, not the utility's compliance record.
No reader results for Modesto yet - yours would be the first. A hardness or TDS number from a $10 strip kit is enough to start the map.
Help build the first reader-sourced water map. Enter whatever your test strip, TDS pen or lab report shows - one number is enough.
Modesto ranks #160 of 163 graded California cities.
Deep-dive guides for the specific contaminants EPA data flagged in Modesto's water, with removal options for each.
Modesto, CA tap water is legal to drink but grades D on EPA's records, mainly because of PFOA or PFOS measured at or above the 4 ppt federal limit in 2023–2025 EPA sampling and lead at 12 ppb (90th percentile) — under the 15 ppb action level but above 5 ppb. A certified filter matched to those findings is a reasonable precaution.
MODESTO, CITY OF's most recent Lead and Copper Rule result (2025-01-01 to 2027-12-31) was 12 ppb at the 90th percentile, below EPA's 15 ppb action level. Because lead usually comes from service lines and household plumbing, homes built before 1986 should still test at the tap.
Yes. EPA's UCMR5 sampling (2023-11-16 to 2024-09-12) detected PFBS, PFHpA, PFHxA, PFHxS, PFOA, PFOS, PFPeA, with PFOA or PFOS at or above the 4 ppt federal MCL. Reverse osmosis and certified activated-carbon filters reduce PFAS.
No. EPA's SDWIS shows no violations of any kind for MODESTO, CITY OF since 2016.
MODESTO, CITY OF reports purchased surface water as its primary source and serves about 218,771 people (EPA PWSID CA5010010).
We recommend one. Reverse osmosis or a PFAS-certified carbon filter addresses the PFAS result. An NSF/ANSI 53 lead-certified filter addresses lead.
PFOA or PFOS was measured at or above EPA's 4 ppt limit in Modesto's UCMR5 sampling.
Most Popular for Lead
ZeroWater 10-Cup Pitcher
NSF 53 certified to reduce lead & chromium — no installation, the easiest way to start protecting your water today.
Check Price on AmazonCompare direct from Waterdrop
Filters rated for lead reduction
Waterdrop's lead collection — every filter here is selected for lead reduction, so you can compare options rated for this exact problem.
Shop Filters Rated for Lead →Whole-Home Filtration System
Whole-house system — treats every tap at the source
For consistently poor water, a whole-home system filters every faucet, shower, and appliance — the permanent, install-once fix that goes beyond a single point-of-use filter.
Explore Whole-Home SystemsNot sure what filter you need?
Test your tap water first, so you filter for what's actually in it.
Shop Home Water Test Kits →We may earn a commission from Amazon and Waterdrop when you purchase through our links, at no extra cost to you.
Based on contaminants detected in your water, these resources may be helpful:
Find the right filter for your Modesto water quality needs:
Tap water is one piece of the picture — our sister sites cover the rest for Modesto, CA.
Live EPA AirNow AQI, dominant pollutant and forecast.
Predicted indoor radon by ZIP vs. the EPA 4 pCi/L action level.
Arsenic and nitrate risk for homes on a well instead of city water.
Understand your water better with our in-depth guides on contaminants, filtration, and water safety.