Residential plumbing: What does "main loop" mean?

[Stephen Tashiro]

I heard a plumber say that a whole house sediment filter would simple to install at the "main loop". What is the "main loop" in the plumbing for a house? In the case at hand, the main loop appears to be where a pipe in the utility room comes out of the wal and goes back into the wall.

[Jim Becker]

Filtration normally comes after the supply demark before the supply branches to anything for either cold or hot. The specific location might vary slightly, depending on the type of supply and other factors. It sounds like from your description, the one place in your home that the unit can be positioned is in that in-out appearance, so I would suspect it's the first place water flows after it enters the home. In my system, the water comes from the well pump to a pressure tank and then flows out to our acid reduction system. Once it passed through that, it hits a sediment filter before branching to the manifold and water heater for the "original" portion of our home and the branch to our addition. So the filter is in front of ALL actual use. This is all in our basement, BTW.

[Tom M King]

I got my plumbing license in 1975. While I never spent any time around other plumbers, I've never heard the term "main loop".

[Tim Bueler]

I've never heard it referred to as main loop. The "loop" you have in your utility room, does it have a valve there? Is it a more sizeable pipe, 3/4" or larger? If you answer yes to both questions I'd say it's possible that's your main, incoming line from the source and would be an appropriate place to tap for a whole house sediment filter system.

Just a few thoughts/questions.

Why do you need a whole house sediment filter? Are you on a well? Public water system? Small community system? If anything other than a personal well you may want to address excess sediment issues with the supplier.

If you are getting excessive sediment, are you sure you're not getting other contaminants also? If you are on a personal well, water testing by a reputable laboratory might be in order. If you're on some sort of municipal system this should be done as a regular course of action.

[Stephen Tashiro]

Just a few thoughts/questions.

Why do you need a whole house sediment filter?

The sediment filter has been installed, so I have no problems involving whole house sediment filters.

At a completely different house, (built 1976) the water heater is installed in a place where there is no obvious way to provide a drain for a drip pan and and pressure relief. The house is built on a concrete slab. I may have the problem of finding a better location for the water heater. I suppose this involves finding the "main entry" of the water line into the house - whatever term is used to describe that.

I can't tell you specifics about the plumbing at that house yet since I haven't officially bought it.

[Alan Rutherford]

...the water heater is installed in a place where there is no obvious way to provide a drain for a drip pan and and pressure relief......

There are some good ways to handle this problem but in the meantime, $10 or so will get you a battery-powered alarm with 2 contacts you put where it will get wet if the HWH leaks. If there is any doubt about the positioning of the contacts, wrap a scrap of paper towel around them so it will wick the water to the contacts. You can test with a wet fingertip to see whether it's working and how sensitive it is, and how loud.