The lower the water pressure the less waste, however water heaters wont work if pressure is to low.

Unless he has gas waterheaters he won't have to worry about hot water if the power goes out so the low pressure cutoff on the heat shouldn't matter.

True but not to common;o)

Thinking out loud in response to a previous post asking why an elevated tank would be better than a generator for a water supply during a power outage. Some thoughts.
1.A water tank most importantly buffers the supply with the demand if a well only makes 10 gals per min and you need 12 the well would start spitting after a few minutes and this could damage the pump.
2. Filling a pressure tank and pumping up gradient to a tank is the same to the pump on the effluent side of the pump.
3. Fewer start stops for the pump/seems more efficient
4. Water temp increases with the tank in the sun
5.A generator that you would want to depend on for water is pretty expensive and you would need to start it every time you need any significant amount of water.
6. (Only a real redneck can appreciate this) The time honored tradition of ascending the local water tower with a can of paint and a brush to defend your sisters honor. Do water tanks get grafetti in Thailand? Cant say I have noticed.
7. ?

IN THE U.K. EVEN IN A SINGLE FLOOR HOME THE WATER TANK IS IN THE ROOF SPACE AND THE WATER IS JUST GRAVITY FED TO BATHROOM AND KITCHEN