Typical values from 42 sampled wells in Placer County · Full groundwater profile
Quick Answers for Placer County Well Owners
No common nuisance problem in the typical well. The typical Placer well is moderately hard, with iron below the stain threshold and a pH of 7.2.
Is it safe? Only after a lab test that includes arsenic.
What usually fixes it:
Usually nothing beyond routine testing. Most Placer wells need no softener or iron filter, so test before buying equipment.
Not sure what to install? Get a filter recommendation for Placer County homesOn city or county water instead? Your utility publishes an annual water quality report; this page covers private wells. Find your utility's report
On this page (8 sections)
Where to Test Well Water in Placer County
- Your county environmental health department handles private well questions in Placer County; for a water test, use a state-accredited lab, many of which accept mailed or dropped-off samples.
- Certified labs: State Water Board list of accredited labs (ELAP)
Ask the lab for sample bottles and how quickly the sample must reach it before you collect.
What Are You Noticing in Your Water?
Confirm with a lab test before buying equipment.
Explore California Interactive Map
Explore Placer County and nearby counties
Placer County has about 424,000 residents, and its largest communities are Roseville, Rocklin and Lincoln. Homes outside city and community water systems rely on private domestic wells. Wells here tap the Central Valley aquifer system, and the largest DWR groundwater basin in the county is Sacramento Valley – North American.
Across 42 sampled wells, groundwater is moderately hard (5.1 gpg in the typical well). Arsenic, nitrate and chromium-6 were below California limits in most sampled wells, but individual wells vary, so test yours.
In this guide
Groundwater Profile: Placer County
Across 42 sampled wells, the median hardness is 5.1 gpg (moderately hard). At 5.1 gpg, Placer wells run harder than El Dorado (3.2 gpg), softer than Sacramento (6.8 gpg) and Yuba (8 gpg) and about as soft as Nevada (4.6 gpg) next door. The largest California DWR Bulletin 118 groundwater basins in the county are Sacramento Valley – North American and Martis Valley.
Another address? Check hardness by ZIP code.
No contaminant tracked here was above its EPA guideline in the typical (median) sampled well.
Arsenic, Nitrate, Chromium-6 and Salinity in Placer County
| Contaminant | Typical well | Wells above limit | California standard |
|---|---|---|---|
| Arsenic | 1.3 µg/L | 7% of 42 | 10 µg/L (primary MCL) |
| Nitrate (as nitrogen) | 0.08 mg/L | 2% of 61 | 10 mg/L (primary MCL) |
| Chromium-6 | 0.15 µg/L | 0% of 26 | 10 µg/L (primary MCL since Oct. 1, 2024) |
| Salinity (dissolved solids) | 172 mg/L | 2% of 42 | 500 mg/L recommended, 1,000 mg/L upper (secondary) |
| Hardness | 5.1 gpg | 31% of 42 | No limit; above 7 gpg is hard |
Typical well = median. Standards: State Water Board; samples: Water Quality Portal, since 2000.
How Placer County Compares to California and the U.S.
See How Placer County Compares to California & the US
| Share of wells with… | Placer CountyPlacer | CaliforniaCA | United StatesUS |
|---|---|---|---|
| Hard water (above 7 gpg) | 31% | 64% | 60% |
| Iron above 0.3 mg/L | 7% | 9% | 19% |
| Manganese above 0.05 mg/L | 12% | 22% | 21% |
| Dissolved solids above 500 mg/L | 2% | 38% | 15% |
| Acidic water (pH below 6.5) | 3% | 2% | 14% |
| Nitrate above 10 mg/L (EPA limit) | 2% | 9% | 4% |
| Arsenic above 10 µg/L (EPA limit) | 7% | 14% | 7% |
| Chromium-6 above 10 µg/L (California limit) | 0% | 6% | — |
| Median hardness | 5.1 gpg | 9.9 gpg | — |
| Median pH | 7.2 | 7.6 | 7.3 |
Sources: Water Quality Portal (since 2000); US: USGS Circular 1332. Highlighted: well above the US share.
See what a typical Placer County well needs
Pre-filled with the Placer medians. Swap in your own results.
Testing Your Well in Placer County
In California, county environmental health departments handle private well permits and can advise on testing. For bacteria, nitrate, arsenic or a full panel, use a laboratory accredited by California’s Environmental Laboratory Accreditation Program (ELAP); the State Water Board’s certified lab map lists them.
What to test for in Placer County:
- Bacteria (total coliform and E. coli), nitrate and arsenic, at least once a year (California State Water Resources Control Board recommendation)
- After any flood, new well work or a change in taste, color or smell
Which tests to order and how: how to test well water.
After a positive coliform test, work out the bleach dose and shock the well and retest 10 to 14 days later.
Nearby Counties
Placer County borders these counties with published reports:
El Dorado County
3.2 gpg hardnessNevada County
4.6 gpg hardnessSacramento County
6.8 gpg hardness · Arsenic, Chromium-6Sutter County
15.2 gpg hardness · Hardness, ArsenicYuba County
8 gpg hardness · HardnessCounties with similar well water
Not next door, but the groundwater is much the same:
Frequently Asked Questions
Is well water in Placer County safe to drink?
It depends on your own well. In Placer County lab records, arsenic exceeded the 10 µg/L limit in 7% of 42 sampled wells. These have no taste or smell, so test for them, and for bacteria, before drinking untreated water.
How hard is well water in Placer County?
5.1 gpg (88 mg/L) in the typical well, based on 42 samples: moderately hard on the USGS scale, against a California median of 9.9 gpg. 31% of sampled wells top 7 gpg, where a softener usually pays off.
Is iron a problem in Placer County well water?
Usually not. Across 42 sampled wells the median is 0 mg/L, under the 0.3 mg/L stain threshold, though 7% of wells exceed it. If your fixtures stain, test for iron and manganese before buying a filter.
Is arsenic a problem in Placer County well water?
Yes for some wells: 7% of 42 sampled wells exceeded the 10 µg/L arsenic limit. Long-term exposure raises cancer risk, so test, and treat with reverse osmosis if needed.
Why does my well water smell like rotten eggs in Placer County?
Public lab records include sulfide results for only 10 wells in Placer, not enough to judge. The smell comes from hydrogen sulfide; a sulfide test confirms it, and at household levels it is a nuisance, not a health hazard.
Is chromium-6 a concern in Placer County well water?
Hexavalent chromium was above California’s 10 µg/L drinking water limit in 0% of 26 sampled wells in Placer County. The limit took effect on October 1, 2024. It has no taste or smell, so only a lab test shows whether your well is affected; reverse osmosis is a common household treatment.
Does boiling well water make it safe to drink in Placer County?
Only against germs. A one-minute rolling boil kills bacteria after a positive test or a boil water notice, but it leaves minerals and chemicals behind in less water. See what boiling can and cannot fix.
How often should I test my well water in Placer County?
The California State Water Resources Control Board recommends testing domestic wells every year, including for bacteria, nitrate and arsenic, and again after flooding or well repairs.
Written by Well Water Advisor Editorial Team.