Concrete or polyethylene cistern: what to check before choosing

Record the tank capacity, dimensions, access opening, inlet, outlet and overflow arrangement. Photograph labels on a manufactured tank. For a built-in concrete cistern, ask for drawings and records of waterproofing or repairs. Check the condition of the existing tank, whatever material it is made from.

To identify the parts, read how a cistern works. For capacity planning, use the tank-sizing guide.

• Who will assess visible cracks, movement or leakage and specify any repair?
• Which coating or lining is proposed, and is its documented use suitable for drinking-water contact?
• How will the tank be isolated, drained, cleaned and returned to service?
• Can the access cover be secured, and can maintenance be completed without damaging the installation?

Ask the contractor to price structural repairs, surface preparation, coating and plumbing separately. Keep product names and instructions with your maintenance records.

• What is the exact model and rated capacity?
• Does the manufacturer approve the intended above-ground or buried installation?
• What foundation, surrounding support and access clearances does that model require?
• Are the fittings, lid and replacement parts included, and who handles warranty work?

Check the actual model instructions before excavation or installation. Compare the complete installed quote, including any removal of the old tank.

NSF/ANSI 61 addresses substances that water-contact components can impart to drinking water. It does not establish treatment performance or microbial control. Ask for documentation for the exact tank, coating or component being supplied. Read NSF’s explanation of the standard.

Assessing the tank does not establish whether its water is safe to drink. For that, start with water testing.