Arsenic
Summary: Arsenic is a naturally occurring element that can dissolve from rock into groundwater. It has no taste, color, or odor—so the only way to know if it’s there is to test.
Where does arsenic come from?
- Natural geology: Bedrock aquifers in many U.S. regions (common in parts of the West and Northeast).
- Less common sources: Legacy pesticides, industrial sites, or old disposal areas.
Why homeowners should care
Arsenic can be present even when water looks and tastes fine. Levels can change with season, drought, heavy rain, or after well work—so a “safe” result years ago doesn’t guarantee safety today.
How we test
HealthWaterLab uses a laboratory colorimetric method appropriate for drinking water screening. For private wells, we recommend periodic testing, and a confirmation test if results are close to local or federal limits.
How to read your result
- Compare your number with federal/state limits and your local guidance.
- Retest if your value is near the limit or if water conditions recently changed (flooding, drought, pump/plumbing work).
- Track results over time—trend lines help you decide on treatment.
If arsenic is detected: practical next steps
- Reverse osmosis (RO) at the kitchen sink: RO is a membrane system installed under the sink that forces water through a very fine filter. It’s one of the most reliable ways to reduce arsenic for drinking and cooking.
- Whole-home options: Adsorptive media or anion exchange can treat all taps when house-wide reduction is desired.
- Maintain & verify: Replace filters/media on schedule and confirm performance with a follow-up test.
FAQ
Does boiling remove arsenic?
No. Boiling actually concentrates it. Use certified treatment such as reverse osmosis (RO) or specialized media.
Which faucet should I test?
Start with the kitchen cold-water tap. If you have a treated/filtered faucet, test that too to verify removal.
Will a carbon pitcher or fridge filter help?
Standard carbon alone is unreliable for arsenic. Use RO or a system specifically certified for arsenic reduction.
What is reverse osmosis (RO)?
A compact under-sink system that pushes water through a very fine membrane. It’s one of the most dependable ways to reduce arsenic for drinking/cooking water.
How often should I test for arsenic?
For private wells: once a year, and always after changes (pump/plumbing work, droughts/floods). If results are near a limit, confirm with a follow-up test.
Do public (city) water customers need to test?
Cities monitor at the system level, not your kitchen tap. If you have old plumbing or just want peace of mind, a tap test is reasonable.
What’s the difference between arsenic III and V?
Two forms (As(III) & As(V)). Some treatments remove As(V) better. Many systems convert As(III) to As(V) before removal; RO treats both well.
Will a water softener remove arsenic?
No. Softeners target hardness (calcium/magnesium). Use RO or certified arsenic media instead.
Is showering safe if arsenic is present?
Arsenic exposure is mainly from drinking/cooking water, not normal showering. Focus treatment on water you ingest.
Should I mix baby formula with RO water?
Yes—use treated water (e.g., RO) for infant formula when arsenic is detected or suspected. Confirm performance with a follow-up test.
Does cooking (like boiling rice) change arsenic levels?
Cooking with untreated water can add arsenic to food. Use treated/RO water for drinking and cooking.
Why did my result change since last year?
Well chemistry can shift with season, drought/rain, or well work. That’s why periodic testing and trend tracking matter.
How do I know my treatment is still working?
Replace filters/media on schedule and verify with a lab test at the treated faucet. Keep simple logs of filter dates and results.
How fast can I get results?
Lab turnaround varies by method and workload. Check current timing and kits at HealthWaterLab.com.
Need help choosing a test or system? Visit HealthWaterLab.com for kits, step-by-step sampling guides, and expert support.