Hello all,

I recently replaced my 3/4 HP pump attached to a large pressure/holding tank circa 1975 with a new 1/2 HP and a small pressure tank (2 years old was working fine at the time of the change). I am drawing lake water to feed a cottage with 2 sinks, 1 shower and 1 toilet. There is a 6 gallon Point Of Use hot water heater. The intake distance it about 20 feet and the distance to the cottage is about 45 feet up hill

The pump I am now using I had at my previous cottage and functioned very well, although it was not supporting as many faucets.

It takes several minutes for the pump to pressurize to 40PSI. Once at 40 PSI it will hold steady. BUT once I flush the toilet I lose pressure (down to about 5 PSI).

There are no leaks and the pump maintains its prime, just the rapid pressure drop. The only difference between the two locations is the PVC pipe from the pump to the cottage is larger in diameter.

Thanks in advance for any ideas, I have struggled the whole season so far with the 3/4 HP with the big old flakey holding/pressure tank and now I have a new frustration with this new pump/tank combo...