What to do with a flooded private well

Stop using the well

If floodwater reached the well, surrounded it, entered the well pit, damaged well equipment, or may have contaminated the well:

• do not drink the water;
• do not use it for cooking, brushing teeth, making ice, preparing formula, washing food, washing dishes, or giving water to pets; and
• do not bathe or wash with it until local officials or the contractor responsible for the work says that stage is complete.

Use commercially bottled water until the well has been inspected, disinfected when required, and tested according to local guidance.

A private well is not monitored or treated by a public water utility. Clear-looking water and restored water pressure do not show that it is safe.

Stay away from electrical and physical hazards

Do not approach a flooded well pump, control box, electrical connection, or standing water near electrical equipment.

Do not turn the pump on. Do not enter a well pit. Do not handle wiring or clear debris around the well until power has been safely disconnected and the area has been checked.

Floodwater may conceal downed lines, sharp debris, holes, unstable ground, and damaged equipment. A well pit can also contain dangerous gases or vapors.

A qualified electrician, well contractor, or pump contractor should inspect the wiring and equipment before power is restored.

Check for possible chemical contamination

Use only bottled water and contact the local health or environmental department if:

• the water smells like fuel or chemicals;
• fuel, pesticides, industrial chemicals, sewage, or another contaminant may have entered the floodwater;
• a storage tank or chemical container leaked nearby; or
• officials identify a chemical, toxin, or radioactive contamination concern.

Boiling and ordinary well disinfection do not make water contaminated with fuel, toxic chemicals, or radioactive materials safe.

Arrange inspection, disinfection, and testing

Contact:

1. the local or state health department or environmental agency for area-specific instructions and the required tests;
2. a qualified well or pump contractor to inspect the well, pump, casing, cap, pressure system, and associated plumbing; and
3. a state-certified drinking-water laboratory for sampling and testing.

CDC recommends that well disinfection after an emergency be performed by a well or pump contractor because the work can involve electricity, damaged equipment, concentrated chlorine, and well-specific calculations.

The contractor and health department should determine whether the well needs repair, flushing, disinfection, or additional treatment before a sample is collected.

Test at the correct time

CDC advises waiting at least 7 to 10 days after disinfection before collecting the confirmation sample so chlorine has been flushed from the system.

The confirmation testing should include total coliform bacteria and either E. coli or fecal coliform bacteria. The health or environmental department may require tests for nitrates, fuel-related compounds, pesticides, or other local contaminants based on the flood and nearby land uses.

Until testing is complete, use bottled water or follow the local authority's instructions for boiling well water after disinfection. Do not use boiling as an interim measure when chemical contamination is suspected.

If bacteria are found, repeat the corrective process with the contractor and test again. Follow the health department's interpretation of chemical results. Do not decide that a detected chemical level is acceptable without the appropriate authority or qualified professional.

CDC also advises follow-up bacterial testing 2 to 4 weeks after the first post-disinfection test and again 3 to 4 months later.

Return to normal use only after the required result

Record:

• the date and extent of flooding;
• observed damage or unusual odor, color, or pressure;
• the health department and contractor contacted;
• inspection, repair, flushing, and disinfection dates;
• the certified laboratory and tests ordered;
• sample dates and results;
• the person or authority who interpreted the results; and
• the date normal use was authorized.

A completed disinfection step is not the same as a passing test. A passing bacterial result does not rule out a chemical that was never tested.

Do not

• Do not drink from or wash with a flooded well.
• Do not approach flooded electrical equipment or turn the pump back on yourself.
• Do not enter a well pit.
• Do not use clear appearance, normal odor, or restored pressure as proof of safety.
• Do not boil water that may contain fuel or toxic chemicals and call it safe.
• Do not improvise a bleach quantity without identifying the well type, dimensions, system components, and local instructions.
• Do not collect the confirmation sample before the required post-disinfection interval.
• Do not mark the well safe merely because disinfection was completed.

Next action

Switch the household to bottled water. Save the local health department and well-contractor contact information, then record each stage separately: stop use, inspection, repair or disinfection, sample collected, result interpreted, and normal use authorized.