ask the experts - i'm looking for advice

my water supply (drilled well) is 1" copper that feeds a pex manifold with 1/2" distribution lines. i want to install a whole house waterfilter. the one i picked up has 3/4" inlet and outlet. it would be installed before the manifolds. will the 1" to 3/4" reduction and the introduction of a water filter affect my water pressure?

advanced thanks!
andy frost

Pressure will remain the same, but your flow rate will be reduced. The impact will depend on how many fixtures normally operate at the same time.

Water Filters, water softeners, backflow preventers, temperature balancing valves and similar devices all reduce water pressure regardless of pipe diameter and must be accounted for when sizing pipes for the entire distribution system.

Depending upon where the water filter is located relevent to the highest fixtures and developed length of the pipe, there can be a susbstantial overall pressure reducing effect from the installation of a whole house filter.

The manufacturer of the appliance should have the expected pressure reduction rating listed within the technical data sheet for the product.

Pressure (PSI) is not affected by filters and such (except for pressure regulators). Flow rate (GPM) is reduced by all of these things you mentioned.

hmmm, two teenage daughters – all the fixtures all the time!
seriously, we could have two showers, washing machine & a toilet going in unison.

i’m trying to sift out any grit before the water enters distribution. i’ve got no other water issues, just trying some prevention. i guess i’d put a filter at the kitchen if i test for some potability issues.

any suggestions for whole house?


Andrew, GE has a 1" fitting on a whole house filter, you can pick one up at Home Depot. about $50.00 You may also want to upsize your preasure tank as well if you are looking for capacity