Filters may be placed on the supply main in the cellar if desired. They will remove sediment and screen the water. They do not remove salts in solution or bacteria. If employed, filters must be arranged to allow of ready cleaning and washing. The waste discharge must not connect directly with the house drains. Direct supply branches should be laid to the kitchen and butlers' sinks and fixtures where drinking-water will be drawn.

If the water pressure is so strong as to cause wear of the faucets, or so light as to fail on upper floors, a tinned copper-lined or iron house tank should be placed in the attic and supplied through a ball cock or filled by a pump. The tank should have a large overflow, safe-waste, and emptying pipe, discharging upon a roof or over a fixture with a large outlet. The overflow must not connect with the drain pipes. Provide a flap valve on the end of overflow pipe. The tank should be cleaned frequently. Provide a dust-proof cover with ventilation opening protected by wire gauze and a cloth screen.