Typical values from 58 sampled wells in Nevada County · Full groundwater profile
What Nevada County Wells Usually Need
No common nuisance problem in the typical well. The typical Nevada well is moderately hard, with iron below the stain threshold and a pH of 7.2.
Drink it untreated? Not untreated until a lab has checked it for arsenic.
What a typical home here installs:
Usually nothing beyond routine testing. Most Nevada wells need no softener or iron filter, so test before buying equipment.
Not sure what to install? Get a filter recommendation for Nevada 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 Nevada County
- Your county environmental health department handles private well questions in Nevada 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.
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Explore Nevada County and nearby counties
Nevada County has about 102,000 residents, and its largest communities are Truckee, Grass Valley and Nevada City. Homes outside city and community water systems rely on private domestic wells. Wells here draw from small local groundwater basins and fractured bedrock, so water quality can change a lot from one property to the next.
Across 58 sampled wells, groundwater is moderately hard (4.6 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: Nevada County
Across 58 sampled wells, the median hardness is 4.6 gpg (moderately hard). At 4.6 gpg, Nevada wells run softer than Placer (5.1 gpg) and Yuba (8 gpg) next door. The largest California DWR Bulletin 118 groundwater basin in the county is 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 Nevada County
| Contaminant | Typical well | Wells above limit | California standard |
|---|---|---|---|
| Arsenic | 0.4 µg/L | 5% of 58 | 10 µg/L (primary MCL) |
| Nitrate (as nitrogen) | 0.11 mg/L | 0% of 58 | 10 mg/L (primary MCL) |
| Chromium-6 | 0 µg/L | 0% of 25 | 10 µg/L (primary MCL since Oct. 1, 2024) |
| Salinity (dissolved solids) | 148 mg/L | 0% of 58 | 500 mg/L recommended, 1,000 mg/L upper (secondary) |
| Hardness | 4.6 gpg | 31% of 58 | No limit; above 7 gpg is hard |
Typical well = median. Standards: State Water Board; samples: Water Quality Portal, since 2000.
How Nevada County Compares to California and the U.S.
See How Nevada County Compares to California & the US
| Share of wells with… | Nevada CountyNevada | CaliforniaCA | United StatesUS |
|---|---|---|---|
| Hard water (above 7 gpg) | 31% | 64% | 60% |
| Iron above 0.3 mg/L | 9% | 9% | 19% |
| Manganese above 0.05 mg/L | 16% | 22% | 21% |
| Dissolved solids above 500 mg/L | 2% | 38% | 15% |
| Acidic water (pH below 6.5) | 24% | 2% | 14% |
| Nitrate above 10 mg/L (EPA limit) | 0% | 9% | 4% |
| Arsenic above 10 µg/L (EPA limit) | 5% | 14% | 7% |
| Chromium-6 above 10 µg/L (California limit) | 0% | 6% | — |
| Median hardness | 4.6 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 Nevada County well needs
Pre-filled with the Nevada medians. Swap in your own results.
Testing Your Well in Nevada 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 Nevada 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, shock the well with the right bleach dose and retest 10 to 14 days later.
Nearby Counties
Nevada County borders these counties with published reports:
Counties with similar well water
Not next door, but the groundwater is much the same:
Frequently Asked Questions
Is well water in Nevada County safe to drink?
Many wells are fine, but in county records arsenic exceeded the 10 µg/L limit in 5% of 58 sampled wells. Have your water tested for these and for bacteria before you drink it untreated.
How hard is well water in Nevada County?
Moderately hard. The median Nevada well tests at 4.6 grains per gallon across 58 sampled wells (California median: 9.9 gpg), and 31% are above the 7 gpg mark where most homes add a softener.
Is iron a problem in Nevada County well water?
The median iron level across 58 sampled wells is 0.01 mg/L, below the EPA aesthetic guideline of 0.3 mg/L, and 9% of wells exceed it. Most wells will not stain, but if yours does, a lab test tells you whether iron or manganese is the cause.
Is arsenic a problem in Nevada County well water?
In 5% of 58 sampled wells, arsenic was above the 10 µg/L drinking water limit. It has no taste, color or smell, so only a lab test finds it; reverse osmosis at the kitchen tap or a whole-house arsenic filter removes it.
Why does my well water smell like rotten eggs in Nevada County?
Public lab records include sulfide results for only 11 wells in Nevada, 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 Nevada County well water?
Hexavalent chromium was above California’s 10 µg/L drinking water limit in 0% of 25 sampled wells in Nevada 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 Nevada County?
Boiling handles bacteria and nothing else. It does not soften Nevada water, remove iron or take out nitrate, which ends up more concentrated. Read when boiling helps and when it hurts.
How often should I test my well water in Nevada 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.