I recommend having a well or large cistern for backup water use when municipal water is unavailable in a prolonged crisis, but you still need a reliable way to get the water out of the ground if grid power is down. As usual, I recommend multiple options as backup—solar power or windmill pumps and a manual backup pump with spare parts for each system. You should also have spare pipe and fittings on hand for repairs and new configurations.
First consider adding solar to your grid power source. Most grid-powered well pumps have a high startup voltage draw and require a larger inverter and solar array. These AC well pumps are designed to provide high pressure and volume and typically have a long life but they use more power per gallon than 12V DC pumps. Because these pumps are usually already installed with a well, buying bigger solar equipment instead of new pumps often makes sense. The downside is this will draw heavily on your batteries at night unless you get enough pressure tank capacity so the pump doesn’t have to turn on as often.
The second option is a small 12V submersible pump to a holding tank. These DC pumps are very efficient at pumping small, constant volumes of water, slowly through a 1/2″ sized pipe, to fill a large holding tank or cistern. The size of the cistern will vary but you will need 10-20 gallons per day for livestock (depending on the weather), and 10-100 gallons per person (depending on washing needs) according to Wholesale Solar. If you can put your tank or cistern on a hill above your residence you can get gravity pressure (typically at least 20 feet above the faucet is required to get usable pressure. Use a size larger diameter pipe on the outlet side to help it flow freely).
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