Hardness
Very Hard
187.5 PPM · 11 GPG
Local water dashboard
Official source aggregationA source-transparent look at local hardness, associated public water systems, EPA compliance history, and the measurements that are—and are not—available for Orange County.
At a glance
EPA quarter 2026Q2
Hardness
Very Hard
187.5 PPM · 11 GPG
Compliance screen
No active flag
0 active health-based records
Lead 90th percentile
0.0015 mg/L
10% of action level
Utility match
1 system
Serves 139,461 people system-wide
Hardness meter
Estimated local hardness
USGS hardness classification scale
187.5 PPM
Parts per million
187.5
mg/L as CaCO₃ equivalent
Grains per gallon
11
1 GPG ≈ 17.1 PPM
What this means at home
At 187.5 PPM, mineral scale can build up on fixtures and heating elements, reduce soap lather, and leave visible spotting. Hardness is primarily an aesthetic and appliance concern—not itself a tap-water safety rating.
USGS sites used
20
Nearest site
12 mi
Observation range
Jan 6, 2016–May 14, 2026
Estimate confidence
Moderate
Median of the latest qualifying hardness observation at each nearby monitoring site. Nearest monitoring location: S LEGG LK AB WHITTIER NARROWS DAM NR MONTEBELLO CA (Lake, Reservoir, Impoundment).USGS source documentation ↗
Regional context
These comparisons use other indexed ZIP estimates, not utility tap samples. They help show local context without replacing a household test.
Fullerton median
183 PPM
5 PPM higher4 indexed ZIP readings · Range 181–187.5 PPM
California median
189 PPM
About the same678 indexed ZIP readings · Range 3.3–728.5 PPM
EPA benchmark screen
Available numerical results from associated SDWIS community water systems, compared with the applicable action level or federal MCL. Federal measured-value coverage is incomplete.
Lead (PB90)
0.0015 mg/L
Reported Dec 31, 2024
Copper (CU90)
Not available
No numerical 90th-percentile result
Numerical coverage
1 comparable result
Missing values remain blank; absence is not treated as a pass.
Measured in mg/L
Local 0.0015
EPA limit 0.015
100% line = listed limit
No violation record was returned for the associated systems in the imported lookback window beginning Jan 1, 2021.
No reported violation does not prove that every contaminant was tested or absent; SDWIS measured values are incomplete and lag state records.
Solutions matcher
Matched to Fullerton ZIP 92833 using 187.5 PPM nearby hardness and 1 reported measurement benchmarks.
Scale protection
187.5 PPM is 2× the high-hardness trigger used by this matcher.
Designed to reduce scale on fixtures, water heaters, glassware, and plumbing throughout the home.
Compare whole-house systemsAffiliate disclosure: we may earn a commission from qualifying purchases, at no added cost to you. Product matching is educational and does not replace certified water testing.
Nearby indexed reports
Estimates can differ across a city because monitoring locations and associated systems differ.
Frequently asked
EPA ECHO shows no active health-based violation for the associated systems in this reporting snapshot. This does not prove every contaminant is absent; federal records can lag and household plumbing can change tap conditions.
Nearby USGS observations produce an estimate of 187.5 PPM, or 11 grains per gallon, classified as very hard. This is not a household tap measurement.
At 187.5 PPM, a correctly sized whole-house softener can reduce scale and hard-water spotting. It does not replace contaminant filtration.