How and why to test your well water in Texas
Private wells in Texas aren't regulated like city water, so the owner is responsible for making sure the water is safe. Here are the basics, drawn from Texas Water Development Board and EPA guidance.
Why test
- Bacteria such as coliform and E. coli can enter after floods, from nearby septic systems, or through a damaged well cap. You can't see, smell or taste them.
- Some Texas aquifers contain naturally occurring arsenic, fluoride, nitrate, radium or high salts.
- A baseline test gives you a record if nearby drilling, construction or flooding changes your water later.
What to test
- Every year: total coliform / E. coli bacteria, and nitrate.
- Every few years, or when buying a home: a broader panel (pH, hardness, iron, manganese, total dissolved solids, arsenic, fluoride).
- If there is oil and gas activity nearby: ask a lab about hydrocarbon (TPH) testing.
When to test right away
- After flooding, or after any work on the well or plumbing.
- If the taste, color or smell changes, or anyone in the house gets a stomach illness.
- Before using the well for an infant or pregnant household member.
How to collect a sample
- Call the lab first and ask for its sterile sample bottle and instructions.
- Take the sample from a cold-water tap without an aerator or filter, after running the water.
- Keep it cold and deliver it within the lab's time limit. Bacteria samples are usually due within 30–36 hours.
What it costs
The TWDB says costs range from about $20 for a basic bacteria test up to about $400 for a full drinking-water standards analysis. Ask the lab for a quote. Some groundwater conservation districts test for free or at a reduced cost.
If results come back high
Positive bacteria results usually mean the well should be shock-chlorinated and retested. For chemical results above the drinking-water limits, talk to your local health department about treatment options.