# Leak in PVC under walkway



## joecaption (Nov 30, 2011)

Are you talking about the 3 or 4" PVC line?
Looks like a SCH. 20 drain line for a french drain or your down spouts.


----------



## xxxshiftxxx (Apr 5, 2013)

joecaption said:


> Are you talking about the 3 or 4" PVC line?
> Looks like a SCH. 20 drain line for a french drain or your down spouts.


No, the water is leaking from under the walkway some place from my sprinkler supply PVC line. The last picture shows the small PVC line running from backyard under walkway. The water is flowing out of the large drain pipe in the first picture when I turn on the water supply on the anti siphon valve...

So, system is leaking under walkway and water is draining through the large drain pipe.

The small white PVC that runs water to back yard is leaking. I cannont find that in the front, but its right next to drain pipe in rear...

Would the turn this line and take around other side of house?


----------



## Seattle2k (Mar 26, 2012)

xxxshiftxxx said:


> Would the turn this line and take around other side of house?


Say what?


----------



## xxxshiftxxx (Apr 5, 2013)

Seattle2k said:


> Say what?


Haha, my bad...

Okay... The last photo shows the small PVC pipe running along the large drain pipe heading under walkway from back of house towards front of house..

The first picture shows large drain pipe coming from under walkway... But there is no PVC pipe coming out with it...

Where the heck does that small PVC pipe go? I thought it would run to the front along the drain pipe.

I need to find this pipe because it is leaking some place under walkway.


----------



## user1007 (Sep 23, 2009)

My guess is the line does not follow the drain but that there is a right angle somewhere. Someone laid the drain and irrigation and then poured the slab over the angled joint.

Does the valve actually water anything? Maybe it is legacy, was capped off and once watered plants before that walk was poured? That makes no sense though if you say the water supply for the valve is on the other end of the sidewalk.


----------



## xxxshiftxxx (Apr 5, 2013)

sdsester said:


> My guess is the line does not follow the drain but that there is a right angle somewhere. Someone laid the drain and irrigation and then poured the slab over the angled joint.
> 
> Does the valve actually water anything? Maybe it is legacy, was capped off and once watered plants before that walk was poured? That makes no sense though if you say the water supply for the valve is on the other end of the sidewalk.


Yes, that back valve supplies the water to the back yard drip system. I really don't want to break up concrete to find this leak... Freaking eh...

Maybe I can get lucky and find the Supply PVC at a spot on the other side of house and re route it and move the rear sprinkler valve... Completely taking the break out of the loop...

Thanks for info


----------



## user1007 (Sep 23, 2009)

Just had a thought. Can you give me the model number of that irrigation valve? Guesses to its age?

It may not be able to handle the low flow rates of drip irrigation. Simple switch out could fix your problems. Still concerns me it is backflushing somewhere but that may be your anti-syphon/backflow valve just doing what it should and is supposed to do or it needs a simple rebuild too. 

Sometimes legacy irrigation valves built to handle large residential flow rates and lots of water pressure fail to function well under minimal conditions. 

Remember your lawn sprinkler system needed around 70psi and depending on how many heads you had and the usual residential supply of  8-12 gallons per minute of water flow. Drip needs next to nothing in water pressure for most residential systems. Most residential drip emitters draw between .5-12 gallons per hour. If you are putting pressure and water in minutes or gallons per hour on a system that cannot take it because the valve flow rate is set to high or a master valve to the system insists it need the water because it remembers a golf course? It has to back all the water and pressure up to the backflow and anti-syphon valve. If working correctly, it's job is to overflow excess before it gets into your tub and shower.

I really hope some idiot did not pour concrete over your plumbing situation. Jackhammers build character though. Every man or woman should have to work one once.


----------



## djlandkpl (Jan 29, 2013)

Looks like a regular Rain Bird. The low pressure valves are bigger and usually have an inline filter. Even with drop on a regular valve it should not cause the backflow to blow water.


----------



## user1007 (Sep 23, 2009)

Low flow rate valve is what I was wondering about. Not low pressure. But let me think about this. Remember your drip system needs near no pressure AND gallons per hour instead of per minute. Some legacy valves cannot handle the low flow rate even when they used to do fine with the pressure. It may be confused. May just need a new rebuild kit too but it was not leaking right? Water is appearing in the backflow direction.


----------



## xxxshiftxxx (Apr 5, 2013)

sdsester said:


> Low flow rate valve is what I was wondering about. Not low pressure. But let me think about this. Remember your drip system needs near no pressure AND gallons per hour instead of per minute. Some legacy valves cannot handle the low flow rate even when they used to do fine with the pressure. It may be confused. May just need a new rebuild kit too but it was not leaking right? Water is appearing in the backflow direction.


Correct, it was not leaking... Just randomly started pooling water next to my house. The water was running out of the drain pipe that runs under my side walkway, meaning I had a leak someplace under there within the irrigation system.. I figured the PVC pipe that supplies water to the rear valve was busted...


----------



## xxxshiftxxx (Apr 5, 2013)

Okay, so I trenched the side of my patio thinking that the water supply line for the rear drips might have turned 90 that way and came up from the other side of house... And might have sprung a leak at the turn under the concrete... Well, dug down about a foot, nothing found...










This is the supply line that comes from no where.

Any other ideas?


----------



## djlandkpl (Jan 29, 2013)

Maybe it goes under the house. I think your idea of rerouting the line.


----------



## xxxshiftxxx (Apr 5, 2013)

Found that ****....

Was way deeper and about 12 inches away from the big drain pipe... This is gunna be interesting fishing new pipe through...

So... 

Connect the new pipe with old pipe and push/ pull through?


----------



## xxxshiftxxx (Apr 5, 2013)

The pipe is going to be a ***** pushing through, it goes in at angle... If it doesn't go through smooth... Any problem just feeding it through the drain pipe, there will still be plenty of room for drainage.


----------



## user1007 (Sep 23, 2009)

That is what I meant to say if I did not. Use the drain pipe for your conduit. If it is a drip circuit you do not need the pressure rating of PVC although you are not talking a huge difference in cost I guess. You probably want PVC on the potential pressure side of the valve though. I would check that that valve is rated for low flow while you are at this?

Might want to note or sketch what you did somewhere for the new homeowner that follows you.


----------



## djlandkpl (Jan 29, 2013)

If you can find it in your area go with Poly pipe. It's easier to use than lengths of PVC.


----------

