Always hear water running through backflow preventer

I have a backflow preventer in my irrigation system connected to the basement water inflow similar to this picture. Is it normal to hear water moving through it all day, even when the irrigation system is off? Thank you.

 

No, not normal. I'd take a look at your water meter when you know water isn't being used anywhere in the house. If the dial is moving at all, you have a leak.

 

If your backflow preventer was just like the one in the picture.... you'd have a shutoff valve that you could try shutting off to see if the noise stopped.

 

If I shut off the valve that leads outdoor, the backflow preventer starts overflowing and leaking water. I waited and this went on at the same rate for over a minute. I can't understand where this water is coming from if the indoor valve is shut off?

Also, the only way to not have any water sounds in the backflow preventer is to shut off the indoor valve and also move both valves in the preventer to the perpendicular position. Is this information helpful?

THank you

 

The backflow preventer is probably lower than your system and that is the water draining back to the low spot. That's not uncommon. It should stop fairly quickly.


That indicates the problem is outside and that your inside water valve does not shut off completely.

If you know where your zones valves are located you could check there and see if you hear water running by one of them. Usually when you can hear the water running.... it comes up thru the ground or at least creates a wet/muddy area. If you had a partially stuck open zone valve you might have water trickling out of some of the sprinkler heads.

 

Sorry for the many questions -- I can't find this specific information anywhere online. Thanks for your help.

I am going to check the water meter while the backflow is on this weekend, to see if any water is being wasted.

One more question. Is ANY sound from the backflow normal when the irrigation is off? Meaning, is there any sound of air coming out of the valve cap or sound of bypassed water running?

Thanks!

 

Take a picture of your system far enough back so we can see your system, It always helps to talk when we can see what you are seeing.
Water shut off no movement of meter or sound from system unless sprinklers valves are leaking than maybe a slight air sound.

 

Here is a picture of the inside basement and outside backflow device. The green solenoid is my Zwave valve attached to a hose.. the spigot is off for that so you can ignore it.

Basically I hear a constant hiss sound when the irrigation is off. I can't tell if that is constant water running. I have to find the water meter and check. The hiss sound goes away when I turn off the top valve in the backflow preventer OR if i turn off the basement inflow valve.

Thanks.

 

We've discussed this.... yes.... your system has a leak. Now it must be found.
Do you know where the other zone valves are ?

 

I don't know where the valves are located. I bought the house and wasn't given the info. I have to call the sprinkler company to investigate the leak.

Another thought I had..... Does the water keep running for a little while after the irrigation is shut off ?

 

Alright, made some progress on my own in advance of the technician coming on Thursday. I dug out the box just below the backflow preventer, where the main line comes in from the backflow preventer. When I turn the main valve on from the basement, this solenoid is spewing water everywhere.... enough so that the whole solenoid becomes submerged by water.....I presume this is where the leak is right? The solenoid is not stopping the water at the main line and that's why the water keeps running. After turning off the main line and waiting, the water dissipated fast, I presume by draining into the soil.

Please see the picture of the solenoid/box. Thanks for your help.
If this is indeed the problem, is it easiest to have the tech replace the solenoid?

 

You must have sandy soil like mine or the water would have filled and overflowed that pit in a few minutes.

It can be a DIY replacement. It is not an easy place to work. You'd first need to clean the valve up to see how it's connected. Normally the valves are in a larger square box with some elbow room.

I'm thinking you may have to dig the valve up.... pull out that enclosure.

Clean it first and we'll go from there.

 

Thanks for your quick reply. So I unscrewed the 4 screws off the valve top and looked inside and found the white ring... It wasn't that dirty but I cleaned it anyway and also checked in the pipe and didn't see any obstruction. I screwed everything back and still same thing, leaking from all directions from the valve.

The valve resembles this one:

https://www.amazon.com/Hunter-PGV-10...solenoid+valve

Is the next step to replace the valve top... or the whole valve? Also what does the small twist thing in the front do? Is it sort of a pressure release valve? Full tightened it leaked as before, but loosened it leaked only out of that part.

Thanks very much.

 

When I said clean the valve up... I meant removing the crap from the pit.

That little knob is to manually open the valve without power.
If it is coming from the valve itself then the valve housing may be cracked.

Just as I feared.... that valve is threaded on both ends which means to replace it you'll have to dig a larger hole to get to the PVC pipe.

 

Alright thanks again....I'll just have the irrigation tech fix it on Thursday. For them this should be a quick fix and hopefully only an hour's worth of labor. Thank you for your help.

 

An hour would be optimistic.... I'd anticipate two hours.

 

Thank you for your help. The technician came last week to replace the master valve under the backflow preventer and this solved the problem.