Typical values from 17 sampled wells in Glenn County · Full groundwater profile
Quick Answers for Glenn County Well Owners
No common nuisance problem in the typical well. The typical Glenn well is very hard, with iron below the stain threshold and a pH of 7.6.
Safe to drink? Usually, going by local records, but confirm with a yearly bacteria and nitrate test.
What usually fixes it:
Usually nothing beyond routine testing. Most Glenn wells need no softener or iron filter, so test before buying equipment.
Not sure what to install? Get a filter recommendation for Glenn 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 Glenn County
- Your county environmental health department handles private well questions in Glenn 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 Glenn County and nearby counties
Glenn County has about 28,000 residents, and its largest communities are Orland and Willows. 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 – Colusa.
Across 17 sampled wells, groundwater is very hard (14.6 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: Glenn County
The largest California DWR Bulletin 118 groundwater basins in the county are Sacramento Valley – Colusa, Sacramento Valley – Corning and Sacramento Valley – Butte.
Another address? Check hardness by ZIP code.
What shows up in local well samples:
- HardnessLimited local data (fewer than 20 samples): individual well testing recommended.
Calcium and magnesium dissolved from limestone. Leaves scale on fixtures and water heaters and reduces soap lather. Not a health risk.
Water softener sizing
Arsenic, Nitrate, Chromium-6 and Salinity in Glenn County
| Contaminant | Typical well | Wells above limit | California standard |
|---|---|---|---|
| Arsenic | 2.1 µg/L | Limited data (17 wells) | 10 µg/L (primary MCL) |
| Nitrate (as nitrogen) | 0.59 mg/L | Limited data (18 wells) | 10 mg/L (primary MCL) |
| Chromium-6 | 0.29 µg/L | 4% of 27 | 10 µg/L (primary MCL since Oct. 1, 2024) |
| Salinity (dissolved solids) | 321 mg/L | Limited data (17 wells) | 500 mg/L recommended, 1,000 mg/L upper (secondary) |
| Hardness | 14.6 gpg | Limited data (17 wells) | No limit; above 7 gpg is hard |
Typical well = median. Standards: State Water Board; samples: Water Quality Portal, since 2000.
How Glenn County Compares to California and the U.S.
See How Glenn County Compares to California & the US
| Share of wells with… | Glenn CountyGlenn | CaliforniaCA | United StatesUS |
|---|---|---|---|
| Hard water (above 7 gpg) | Limited data | 64% | 60% |
| Iron above 0.3 mg/L | Limited data | 9% | 19% |
| Manganese above 0.05 mg/L | Limited data | 22% | 21% |
| Dissolved solids above 500 mg/L | 24% | 38% | 15% |
| Acidic water (pH below 6.5) | 0% | 2% | 14% |
| Nitrate above 10 mg/L (EPA limit) | Limited data | 9% | 4% |
| Arsenic above 10 µg/L (EPA limit) | Limited data | 14% | 7% |
| Chromium-6 above 10 µg/L (California limit) | 4% | 6% | — |
| Median hardness | 14.6 gpg | 9.9 gpg | — |
| Median pH | 7.6 | 7.6 | 7.3 |
Sources: Water Quality Portal (since 2000); US: USGS Circular 1332. Highlighted: well above the US share.
See what a typical Glenn County well needs
Pre-filled with the Glenn medians. Swap in your own results.
Testing Your Well in Glenn 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 Glenn County:
- Bacteria (total coliform and E. coli), nitrate and arsenic, at least once a year (California State Water Resources Control Board recommendation)
- Hardness in grains per gallon (gpg) to size a softener
- 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
Glenn County borders these counties with published reports:
Butte County
6 gpg hardnessColusa County
17.4 gpg hardness · Hardness, ManganeseLake County
9.1 gpg hardness · HardnessMendocino County
6.5 gpg hardnessTehama County
6.7 gpg hardness · Chromium-6Counties with similar well water
Elsewhere in California, these counties have well water like Glenn County:
Frequently Asked Questions
Is well water in Glenn County safe to drink?
Most Glenn wells meet health limits in lab records (17 wells sampled). A yearly bacteria and nitrate test is what tells you about your own well.
How hard is well water in Glenn County?
Groundwater samples from 17 wells in Glenn County have a median hardness of 14.6 grains per gallon (250 mg/L), which the USGS classes as very hard. Limited local data (fewer than 20 samples): individual well testing recommended. The California statewide median is 9.9 gpg.
Is iron a problem in Glenn County well water?
The median iron level across 17 sampled wells is 0 mg/L, below the EPA aesthetic guideline of 0.3 mg/L (limited local data (fewer than 20 samples): individual well testing recommended). Most wells will not stain, but if yours does, a lab test tells you whether iron or manganese is the cause.
Why does my well water smell like rotten eggs in Glenn County?
Public lab records include sulfide results for only 9 wells in Glenn, 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 Glenn County well water?
Hexavalent chromium was above California’s 10 µg/L drinking water limit in 4% of 27 sampled wells in Glenn 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.
Can I install a salt-based water softener in Glenn County?
Usually, but check local rules first. California Water Code Section 13148 lets some local sewer and water recycling agencies limit or ban new salt-discharging softeners to protect recycled water. Homes on septic systems should ask the county environmental health department about brine. A salt-free conditioner discharges no brine, but it reduces scale rather than softening the water.
Does boiling well water make it safe to drink in Glenn County?
Boiling handles bacteria and nothing else. It does not soften Glenn 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 Glenn 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.