AO Smith's water pump product line addresses residential and light commercial well water supply, a segment distinct from municipal water booster pumps. Well pump selection is determined by well depth first, then flow rate requirement, then pressure tank sizing.
AO Smith JS series -- shallow well jet pumps
The AO Smith JS series jet pumps are for wells with static water levels above 25 feet (the practical suction limit for centrifugal pumps at sea level). The JS075 (3/4 HP) and JS100 (1 HP) are the primary residential models. Jet pumps sit above ground or in a pump house and draw water from the well through a suction pipe. The 1 HP JS100 delivers approximately 10-12 GPM at 40 PSI -- adequate for a 3-bedroom home with 2 baths. Jet pumps are simpler to service than submersible pumps (accessible above ground) but are limited to shallow well applications. At $250-$400, JS series pumps are the correct choice for drilled wells with water tables above 25 feet or dug wells.
AO Smith 4SH series -- deep well submersible
AO Smith's 4SH series are 4-inch submersible pumps for wells with static water levels below 25 feet (down to 500+ feet). The motor and pump are a single waterproof unit lowered into the well casing on the discharge pipe. The 4SH05 (1/2 HP), 4SH10 (1 HP), and 4SH15 (1.5 HP) cover residential demand ranges of 5-15 GPM. Submersible pumps are quieter than jet pumps (fully submerged, sound does not transmit to the home), more efficient (no suction lift losses), and fail less frequently under normal conditions. Service requires pulling the pump from the well -- a well contractor task. At $300-$600 for the pump alone (not including installation), the 4SH series is the standard choice for deep well residential systems.
Century motor brand -- AO Smith subsidiary
AO Smith's Century brand produces replacement motors for well pumps, pool pumps, and air handlers. If an AO Smith or compatible pump needs a motor replacement (rather than a full pump replacement), the Century motor catalog covers most residential pump motor frame sizes. Replacement motor cost ($100-$250) is significantly less than full pump replacement ($300-$600+) -- Century makes motor replacement a practical repair option for pump bodies in otherwise good condition.
Pressure tank -- the required companion
Every well pump requires a pressure tank to prevent rapid cycling and protect the motor. AO Smith and its sister brand State Select produce compatible pressure tanks in 5-gallon to 119-gallon sizes. Residential sizing: tank drawdown volume should accommodate 1 minute of pump run time before pressure drops to the cut-in setpoint. For a 1 HP pump at 10 GPM, a 20-gallon tank provides minimum adequate drawdown; 32-44 gallon is the standard residential specification. Under-sized tanks cause short cycling, which is the leading cause of well pump premature failure.