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Cistern Safety

A cistern stores water for the house, garden or livestock, and it needs both safe access and careful water management. This guide covers general ideas and sends you to local experts.

What is a cistern, and why is it a safety concern?

A cistern is a tank or underground chamber that stores water, often rainwater. Some are modern and sealed; others are old, built of brick, concrete or stone. Access hatches may be heavy, hard to see, or poorly secured.

The hazards include falls into the tank, unsafe air in enclosed spaces, slippery or unstable surfaces, and contaminated water. Each hazard calls for a different kind of care.

Older cisterns may have been built long ago with methods that no longer meet current standards. Do not assume that age means strength. Have a qualified person assess any cistern you are unsure about.

• Falls through open or weak hatches.
• Confined space hazards.
• Water that may not be safe to drink.

How should access hatches be secured?

A hatch or lid should be sturdy, kept closed, and secured so that children cannot lift it. Check locks, hinges and seals regularly. A hatch that is cracked, rusted or warped needs attention.

What counts as an adequate cover depends on the type of cistern and local codes. Ask your county building or health department and your extension office. Do not improvise with boards or sheet material.

• Keep hatches closed and secured.
• Check hinges and locks on a schedule.
• Replace damaged lids using professional advice.

Why should you never enter a cistern casually?

Enclosed tanks can contain air that does not support life, and a person can lose consciousness quickly. A person who goes in to help can also be overcome. OSHA treats confined spaces as a serious category of hazard.

Cleaning or repair inside a cistern should be done only by trained people with the right equipment and a rescue plan. If you think a job requires entry, hire a qualified professional, and read OSHA's information on confined spaces.

• Do not enter, lean into or reach far into a cistern.
• Do not rely on smell to judge the air.
• Use trained professionals for any entry.

How do you keep the water safe?

Stored water can become contaminated by debris, animals, insects, roofing materials and runoff. Whether the water is safe to drink depends on the collection method, the maintenance, and treatment.

Your health department can tell you how to test and treat cistern water in your area, and what the rules say about its use. Do not assume that rainwater is automatically safe to drink; follow local guidance.

If the water is used for livestock, ask your veterinarian or extension livestock specialist about water quality needs. Needs differ by species and by use.

• Use screens and covers to keep pests out.
• Test water as officials recommend.
• Do not drink untested cistern water without local advice.

What maintenance should be part of the routine?

Regular tasks include checking gutters and screens, looking for cracks and leaks, and inspecting vents and overflow pipes. Keep a log of what was done and the date.

Cleaning schedules and methods depend on the type of tank and its materials. Follow the manufacturer's instructions, or ask a qualified service provider. Avoid mixing cleaning chemicals, since some combinations release harmful gases.

Pumps and plumbing attached to cisterns carry the same electrical cautions as wells. Use licensed electricians and plumbers for repairs, and never work on electrical equipment in damp conditions.

• Inspect gutters, screens and vents.
• Keep a dated log.
• Do not mix cleaning chemicals.

How can children and visitors be kept safe?

Show children where the cistern is and explain that it is not a place to play, climb or open. Visitors who do not know the farm may not recognize an old cistern, so mention it.

Mark the location clearly if the hatch is flush with the ground. A visible marker also stops mowers and vehicles from damaging the lid.

Ask older children to help watch younger ones and to tell an adult right away if they see a lid out of place. Give them a role that makes them feel trusted rather than only restricted.

What should you do in an emergency?

If a person or animal falls into a cistern, call 911 right away. Do not climb in. The dangers of unsafe air and slippery walls make improvised rescue extremely risky.

Stay at the opening only as long as it is safe, keep others back, and follow the dispatcher's instructions. Seek training in confined space awareness and first aid through recognized providers such as OSHA-authorized trainers and the American Red Cross.

After any emergency, even a near miss, review what happened and fix the weak point, such as a loose lid or an unmarked hatch, before the next season. Be kind in the review; the goal is learning and prevention.

Last reviewed: November 12, 2026. Written by the Farm Safety Editorial Team. See our editorial policy.