I have water running in my basement all the time and I'm not sure why this is the case or if there is a problem. Just above the shutoff for the cold water to the washer, there is a copper pipe off the main line at 90 degrees horizontal and it bends around about 2 feet away. There is water that flows out of it constantly into an open PVC pipe which is set a few inches below it. This PVC pipe then runs over to the sewage drain. The only way to get the water to stop flowing is to turn the water on in the house. Then when the water is turned off in the house, it will start coming of that "branch" pipe again. Does anyone know what this is or if I need to get it fixed? The home inspector for my house did not know what it was when I bought the house.
I believe that when all the water is off in the house, the line is not completely "shut" which is causing a little water the run all the time. Is there a easy fix for this?
Thanks

Is it possible it's connected to a water-powered back-up sump pump?

Hi-Performance Water-Powered Backup Sump Pumps

And the sump pump is broken, so your running on back-up all the time?

But, sewer line discharge of rainwater is illegal in many municipalities.

If the water is not completely shutting off, you have to find out why you can and cannot do in regard to the curb stop.

Many times there are two valves, one on each side of the meter and another at the curb (curb stop).

Many times the homeowner is not allowed to get tools to open/close the valve. Other times a licensed plumber can open and close it and still other times when a licensed plumber can open it.

The best solution is to have the shutoff(s) replaced with ball valves. The simplest is to replace the washer and inspect/ream the seat. My recommendaton is a plumber.

You generally can't get parts for valves and a screw can break off necessitating replacement. You have to be prepared to solder a valve in place and be comfortable doing do, because a pip can bust and you would have no way of stopping the flow of water.

The curb-stop has a recessed pentagon shaped bolt on the cover and marked water.

Its just a copper pipe off the main cold line that has a steady stream of water flowing into a PVC pipe that goes to the sewer line... not sure what its function is for?

That line doesn't sound like it does anything. I'd cap it if it just goes to a drain. I am confused by what you describe. Its ON when the house is OFF and its OFF when the house is ON. This does not sound right.

Yes it has water flowing when the house is "off" and stops when something in the house is "on". The thing is, water should only be in the lines if I turn on a faucet or something right? If they are all off, maybe there is a leak in some kind of valve or regulator?

If it is just a simple tee off th emain line, it would continue to run, just slower when something else ran. I wonder if somedy has somehow rigged a pressure reducing valve, bleedign off water to keep the pressure from going too high. You do have city water? I would check with your neighbors to see if they have pressure reducing valves. If so, you may need one too.

I would install one and remove the pipe, or pay a licensed plumber to do it. Since the pressure reducing valve prevents basck flow, add an expansion tank at the water heater if it doesn't have one.

This still does not make sense for the pipe to have running water when the house main is closed. If its attached to the main there should be no water available unless you have main shut off that's in absolutely terrible shape. That still doesn't answer it because the flow stops when the main is on. " water should only be in the lines if I turn on a faucet or something right?" No, not really, there is water in all of your lines ar all times if the main is open. It flows when you open a faucet but it was in the pipe all of the time.