A lot of homes around Albuquerque run on private wells: in Corrales, Placitas, the East Mountains, the South Valley, around Los Lunas and Belen, and out toward Edgewood. Well water can be excellent. It can also carry things you can't see, smell or taste, and in New Mexico arsenic is the one that comes up most.
Who's responsible for well water?
You are. The EPA's drinking water rules cover public water systems, not private household wells. Your utility neighbors get an annual report with test results; a well owner gets nothing unless they test. The EPA and CDC both state plainly that private well owners are responsible for the safety of their own water.
What to test for, and how often
Every year
The CDC and EPA recommend testing a private well at least once a year for:
- Total coliform bacteria. An indicator that surface water or contamination may be getting into the well.
- Nitrate. Often linked to septic systems, fertilizer or livestock. It's especially important where infants are in the home.
- Total dissolved solids (TDS). A general measure of how much is dissolved in the water.
- pH. Water that's too acidic can corrode plumbing; too alkaline can taste off and scale.
New Mexico additions
The New Mexico Environment Department's private well guidance also recommends testing for arsenic, which occurs naturally in groundwater in many parts of the state, and periodically for uranium. Depending on where you are, fluoride, iron and manganese, sulfate and hardness are also worth including. Ask the lab what panel they suggest for your area.
Test again sooner if
- The water's taste, smell or color changes.
- The well has been flooded, repaired or had its pump replaced.
- Someone in the home is pregnant or you have a new baby.
- You've just bought the home and don't have recent results.
Where to get it tested
A certified laboratory. For results you can rely on, especially for arsenic and uranium, use a lab certified or accredited for drinking water. NMED points well owners to certified labs, and the EPA's Safe Drinking Water Hotline (800-426-4791) can also help you find one. The lab will tell you how to collect the sample; follow their instructions exactly, because a badly collected sample gives a misleading result.
Free screening events. NMED has held water fairs and offered screening at field offices around the state. These are a good way to spot problems, but NMED itself notes that screening is not a substitute for certified lab results, and some screenings don't cover arsenic or uranium. If a screening flags something, confirm it with a certified lab.
Our on-site test measures hardness, TDS, pH, chlorine, iron and sulfur, the things that decide what treatment equipment will work. It doesn't replace a lab test for bacteria, nitrate, arsenic or uranium, and we'll help you arrange one. Details are on the free water test page.
Reading your results
Private wells don't have legal limits, but the federal standards for public water are the sensible benchmark. Here are the ones well owners ask about most:
| Contaminant | Federal limit for public water | Common units on lab reports |
|---|---|---|
| Arsenic | 10 parts per billion | 0.010 mg/L, or 10 µg/L |
| Nitrate (as nitrogen) | 10 parts per million | 10 mg/L as N |
| Uranium | 30 parts per billion | 0.030 mg/L, or 30 µg/L |
| Fluoride | 4 parts per million | 4.0 mg/L |
| Total coliform | Should be absent | "Present" or "Absent" |
Watch the units: 10 µg/L, 10 ppb and 0.010 mg/L are the same amount of arsenic. A result reported as "ND" or "<" a number means nothing was detected above the lab's reporting limit. If anything is near or above these levels, or bacteria are present, talk to the lab and your county or NMED office about next steps.
If arsenic shows up
First, the things that don't work:
- Boiling. It doesn't remove arsenic. Because water evaporates, it can actually concentrate it. The New Mexico Department of Health has warned about exactly this.
- Water softeners. They remove hardness, not arsenic.
- Standard carbon filters, including whole-home carbon. Not designed for arsenic.
The most common household answer is reverse osmosis at the kitchen sink, for the water you drink and cook with. Two details matter:
- Arsenic comes in two forms. Arsenic V is removed well by reverse osmosis. Arsenic III is removed much less reliably unless it's first converted to arsenic V, which is usually done with an oxidizing step ahead of the membrane. Ask your lab whether they can tell you which form you have (called "speciation"), or plan treatment that handles both.
- Choose certified equipment and retest. Look for a system certified for arsenic reduction, then test the treated water from the RO faucet after installation and periodically after that. Performance depends on maintenance, so filters and membranes need changing on schedule.
Whole-house arsenic treatment exists, but for most homes it isn't necessary, since showering in water with low arsenic levels isn't considered a significant route of exposure. Drinking and cooking water is where it counts. If your levels are very high, get advice specific to your results.
More on how we approach drinking water: reverse osmosis systems.
Other common results and what treats them
| Result | Usual approach |
|---|---|
| Bacteria present | Disinfect the well (often shock chlorination by a well professional), find the cause, then retest. Not a job for a softener or filter. |
| High nitrate | Reverse osmosis for drinking water; find and address the source if possible. |
| Hard water | Water softener. See what hardness numbers mean. |
| Iron or manganese staining | A softener can handle small amounts; higher levels need dedicated iron-removal media. |
| Rotten-egg smell | Usually hydrogen sulfide; treatment depends on the level and whether it's in the hot water only. |
My well has been fine for years. Do I still need to test?
Yes. Groundwater conditions change, wells age, and nearby land use changes. Bacteria and nitrate in particular can appear in a well that was clean for years. An annual test is cheap insurance.
Does arsenic in well water have a taste or smell?
No. Arsenic has no taste, color or smell at the levels found in groundwater, which is why testing is the only way to know.
Can I shower in water that has arsenic?
At the levels typically found in New Mexico groundwater, the main concern is drinking and cooking, not skin contact. If your results are unusually high, ask your county or NMED for guidance specific to your numbers.
Sources
- CDC, Guidelines for Testing Well Water
- U.S. EPA, Protect Your Home's Water and Private Drinking Water Wells
- U.S. EPA, Drinking Water Arsenic Rule History
- New Mexico Environment Department, Private Wells
- New Mexico Department of Health, alert on metals in private well water (November 2025)
- Maryland Department of the Environment, Arsenic Treatment in Wells (arsenic III vs. V and pre-oxidation)