Well water testing in Phillips County, Colorado

What official data says about private wells in Phillips County, what to test for, and the state-certified labs nearby.

People on private wells (2015)1,139

About 26% of the county's 4,349 residents. Rank 49 of 64 in Colorado.

Arsenic above EPA’s limit (USGS estimate)about 101 people

95% range 81 to 126 private-well users (2010 base year). Rank 24 of 64 in Colorado.

EPA radon zone (indoor air)Zone 1

Highest potential (average indoor radon may be greater than 4 pCi/L). EPA says the map should not be used to decide whether an individual home needs testing.

Certified labs in this county0

Labs with an address in this county, from the official state lists on this site, matched by ZIP code.

What to test for in Phillips County

Private wells are not regulated like public water: EPA advises owners to test their well every year for total coliform bacteria, nitrates, total dissolved solids and pH. Your state's own schedule:

  • Colorado's health department (CDPHE) recommends testing every year for total coliform bacteria, total dissolved solids, nitrate/nitrite and pH, and every 3 to 5 years for arsenic, copper, fluoride, hardness, iron, lead, manganese and uranium. For a new well or a well with no known testing, it lists a broader panel that includes PFAS and a volatile organic compound (VOC) screen. It says more frequent testing may be needed if pregnant or breastfeeding people, small children or elderly adults drink the water. source
  • CDPHE also says to test if someone in the home becomes pregnant or a child moves in, if people get unexplained stomach illness, if contaminants are found in a neighbor's well, if the water's taste, odor, color or clarity changes, after a spill near the well, after any well repair or part replacement, and after a nearby flood or fire. In areas with historic mining, it suggests you may consider a general metals panel. source
  • Colorado State University Extension says wells used for drinking water should be tested for coliform bacteria every one to two years, along with other water quality parameters, and more often if the well is in poor condition, has been flooded, the septic system has failed, abandoned wells or feed yards are nearby, or visitors have had stomach or intestinal trouble. Its well-care checklist also says to have the well tested once a year for coliform bacteria, nitrate and other contaminants of concern. source

Arsenic. USGS estimates that about 101 people using private wells in Phillips County had arsenic above 10 µg/L, EPA's limit for public water (2010 base year; 95% range 81 to 126). USGS describes this kind of estimate as useful "for broad screening of the population at risk", so it says nothing certain about any one well. Arsenic has no taste or smell: test for it by name.

Radon. EPA puts Phillips County in Zone 1: highest potential (average indoor radon may be greater than 4 pCi/L). That map is about radon in indoor air, and EPA says it should not be used to decide whether an individual home needs testing. If radon is found in your air and you have a well, EPA suggests testing the water too: see radon in well water.

For anything specific to your home (farms nearby, old plumbing, a new baby, a smell or stain), use the which-tests checklist. When the results arrive, check your numbers against EPA's limits.

Estimated private-well users with arsenic above 10 µg/L: Phillips County and Colorado's highest countiespeople (2010 base year)
Show the numbers
ItemValueNote
Alamosa County2,831 people (2010 base year)
El Paso County1,547 people (2010 base year)
Rio Grande County1,382 people (2010 base year)
Elbert County1,257 people (2010 base year)
Douglas County997 people (2010 base year)
Phillips County (this county)101 people (2010 base year)

USGS model estimate for broad screening, not a measurement of any well. Only a test tells you about your own well. Source: USGS, Estimated county level domestic well population with arsenic greater than 10 micrograms per liter (Ayotte, Medalie and Qi, 2017), accessed 2026-11-01.

Testing programs and help in Colorado

  • Anyone with a private well in Colorado can apply to CDPHE's PFAS Testing and Assistance Program (PFAS TAP) for free PFAS testing: a kit is mailed to you, you collect the sample and mail it back with a prepaid label. Households that use the well for drinking and cooking and have PFAS above EPA's drinking water standard can get a free filter dispenser and one year of replacement filters; results from an independent lab test can also qualify. CDPHE says the program is available while supplies last. In 2026 it is doing targeted outreach with Boulder County and the San Luis Valley. source
  • CDPHE says your local public health agency may offer annual water testing, and suggests contacting it or CDPHE's ToxCall line with questions about what to test for. source
  • CDPHE publishes a list of labs it has confirmed can test private well water. It does not endorse any lab, says the list is not exhaustive, and recommends calling the lab to confirm the method, contaminants and price. It notes that results from some labs may not meet the criteria for state or federal assistance programs. source
  • CDPHE's online well water tool lets you enter your lab results and compare them with drinking water guidelines. CDPHE notes that drinking water standards do not apply to private wells, but you can still use them to assess your water. source

Buying a home with a well in Phillips County

Loan test (FHA, VA, USDA) in Phillips County, CO

  • VA. Test results are valid for 90 days from the date the local health authority certifies them, unless the local authority says otherwise. VA’s chapter names no list of contaminants: the water must meet the local health authority’s requirements, or EPA guidelines where it has none. Your lender may ask for specific tests.
  • FHA. A well test is required in the situations FHA’s handbook lists, among others, and the report may not be more than 180 days old at disbursement.
  • USDA. Guaranteed loans need a water quality test for a private well, done by the local health authority or a state-certified lab, and no more than 180 days old at closing.

Lenders can ask for more (extra tests, a particular lab, who takes the sample): ask your lender before you book. Federal rules as read on Nov 3, 2026 source 1 source 2 source 3. Full comparison: VA, FHA and USDA well water test requirements. Loan test kits sold by mail, with price and days to results: kits compared.

State-certified labs in Phillips County

None of the labs on our Colorado list has an address in Phillips County. Labs elsewhere in the state may take samples by mail or courier: ask the lab, and check the hold time for bacteria before you send one.

Labs on the Colorado list whose own websites say they take homeowner samples: Colorado State University (Fort Collins), Three Lakes W/S District (Grand Lake). Use Check my ZIP to sort labs by distance.

See all Colorado labs in the finder and filter by the test you need and by labs that take homeowner samples.

Sources and method Private-well population is the USGS 2015 estimate of people on domestic self-supplied water. The arsenic figure is a USGS model estimate on a 2010 population base, not a count of tested wells. Labs are placed in a county by the ZIP code on the state list. These figures come from different USGS products, years and methods, so they can disagree with each other (for example, the arsenic estimate and the well population use different base years). Read them as context for the county, not as facts about any one well. Checked 1 Nov 2026. General information, not medical advice.
Find a lab94 labs on the Colorado list

Filter by the test you need and by labs that take homeowner samples.

Open the finder →
Not sure what to test?Which tests do I need?

Tick what applies to your home.

Open the checklist →