Monterey County tap water: hardness, PFAS and lead
Monterey County, California has about 436,251 residents (Census 2024 estimate) and 157 community water systems in EPA records. The largest local system is Cal Am Water Company - Monterey, serving about 128,928 people from surface water.
✓ 0 of 6 largest systems with health-based violationsPFAS detected at 1 of 6 sampled systemsHardness 12.9 gpg (low confidence)
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
How hard is Monterey County water?
Cal Am Water Company - MontereyEstimate: untreated local water, not your tap · Low confidence
12.9 gpg(221 mg/L), very hard
Monterey County: median of 882 results from 293 monitoring sites (streams and wells). Utilities may blend or treat water, so your tap can differ.
County estimates: Hard Water Map (hardwatermap.com), CC BY 4.0, derived from the USGS/EPA Water Quality Portal; file generated 2026-07-22. License
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
Softener size at 12.9 gpg
For a 3-person home using 57 gallons per person per day and regenerating weekly, you'd remove about 15,441 grains between regenerations. Suggested size: 24,000 grain. This uses a low-confidence county estimate, so confirm with a test first.
Estimate only. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
The 6 biggest of 157 community water systems on EPA records for this county. Service areas don't follow county lines; your water bill names your provider.
Cal Am Water Company - Monterey
CA2710004 · serves about 128,928 people · Surface water
✓ No health-based violations✓ Lead below action levelPFAS detected (8 types)
Lead 90th percentile: 1 ppb (period starting 2026-01-01). Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
PFBS: highest sample 13.2 ppt (3 of 26 samples); no individual limit; counted in EPA's PFAS mixture (hazard index) limit
PFHxA: highest sample 9.3 ppt (2 of 26 samples); no federal limit
PFPeA: highest sample 9.2 ppt (2 of 26 samples); no federal limit
PFHxS: highest sample 8.7 ppt (2 of 26 samples); federal limit 10.0 ppt as a running annual average, also counted in EPA's PFAS mixture (hazard index) limit (currently in effect; EPA has proposed removing it)
PFOA: highest sample 8.1 ppt (2 of 26 samples); federal limit 4.0 ppt as a running annual average
PFOS: highest sample 7.3 ppt (2 of 26 samples); federal limit 4.0 ppt as a running annual average
PFBA: highest sample 5 ppt (1 of 26 samples); no federal limit
PFHpA: highest sample 3.6 ppt (2 of 26 samples); no federal limit
CA2710001 · serves about 56,253 people · Groundwater
✓ No health-based violations✓ Lead below detection✓ No PFAS detected
Lead 90th percentile: <DL (below the lab detection/reporting limit; reported as 0) (period starting 2023-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
CA2710017 · serves about 38,918 people · Groundwater
✓ No health-based violations✓ Lead below detection✓ No PFAS detected
Lead 90th percentile: <DL (below the lab detection/reporting limit; reported as 0) (period starting 2023-01-01) Older result. Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
CA2710011 · serves about 19,732 people · Groundwater
✓ No health-based violations✓ Lead below detection✓ No PFAS detected
Lead 90th percentile: <DL (below the lab detection/reporting limit; reported as 0) (period starting 2024-01-01). Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
CA2710008 · serves about 18,967 people · Groundwater
✓ No health-based violations✓ Lead below detection✓ No PFAS detected
Lead 90th percentile: <DL (below the lab detection/reporting limit; reported as 0) (period starting 2024-01-01). Action level: 15 ppb (drops to 10 ppb on Nov 1, 2027).
Public-record figures, not a test of your tap. Not 100% accurate or guaranteed. Confirm with a water test, your utility or a qualified pro before you buy or act.
A PFAS detection is not a violation. Federal limits (4 ppt for PFOA and PFOS) apply to running annual averages, with compliance required by 2029. In May 2026 EPA proposed extending the PFOA/PFOS deadline to 2031 and removing other PFAS limits; not final as of 2026-10-21.
Test your own tap
These are public records for whole systems. Your home's pipes, fixtures and any private well can change what you drink. A certified lab test or a hardness test strip gives you your own numbers. Then use our PFAS and lead filter selector to see which certifications to look for.
Common questions about Monterey County water
Is tap water in Monterey County safe to drink?
None of the 6 largest systems here have a health-based violation in EPA records since October 2021. Cal Am Water Company - Monterey's most recent lead 90th percentile was 1 ppb (2026), below the 15 ppb action level. Public records can't guarantee what comes out of your tap, especially with older plumbing, so a home test is the surest check.
How hard is the water in Monterey County?
There's no published utility figure in our data, but untreated local stream and well samples in Monterey County have a median of about 12.9 grains per gallon (221 mg/L, very hard). That's a low-confidence estimate of source water, not your tap, so test before you buy equipment. For a 3-person home at 12.9 gpg, our softener calculator suggests a 24,000 grain unit as a starting point.
Is there PFAS in Monterey County water?
1 of the 6 sampled systems listed here detected at least one PFAS in EPA's UCMR 5 testing, and 2 results were above the level of a federal limit in at least one sample. A detection isn't a violation: federal PFAS limits apply to running annual averages starting in 2029.
Which water system serves my address in Monterey County?
Most homes are served by Cal Am Water Company - Monterey or one of the other systems listed on this page, but service areas don't follow county lines. Your water bill names your provider, and its annual Consumer Confidence Report has the full test results.
Data as of October 21, 2026. Figures are copied from public records and combined with our own calculations; they can be out of date or wrong. Tapped Out isn't affiliated with any utility or the EPA. Written and reviewed by the Tapped Out team. How we calculate · All sources.