Leaky buried pvc - please help!

[dutchstar]

I have a pond which came with the property when we bought the house. From what I can gather, it was originally installed maybe 20yrs+ ago. We have been in the house almost 9yrs.

I’m having a problem and i will try to keep it sufficiently detailed but reasonably brief.

Pond is approx 3600gal and consists of falls, collecting pool, stream and then main pond body at the bottom. I have 4 koi which are about 4-5yrs old and doing well so far.

From the pump (sits in skimmer box), buried PVC line runs alongside the pond to a UV Filter that is above ground (buried under fake rock) and then black flex PVC exits the UV filter and empties into the top of the falls.

Around April, my pump failed. Tsurumi 50PN2.25S - Just stopped working. I ordered a replacement. Since purchase/install in May, I have noticed the pump emptying the box at times and running dry. Pond water level dropping faster than it should. Blew capacitor on the pump and had to replace that. So I figured I had a leak somewhere...

I finally decided to investigate the leak last weekend. Noticed that the ground underneath the UV Filter was wetter than it should have been. Started digging...

I discovered that a joint in the PVC piping had separated (see photos) - it was completely loose and that’s where all the water was leaking out of the system. When I mark the joint line while intact, and then separate the joint (after some laborious digging), it looks like there is only about 1/4” mating in the joint. The depth to the stop is 1/2” so it’s only halfway in. I marked the sections A and B in the photo.

I would really appreciate any advice/thoughts on how to replace this. You can see from the photo that there are two ball-valves (NEITHER of which has been used since before I bought the house). The upper valve allows flow up into the UV filter, and the lower (deeply buried) valve - currently closed - I believe connects to a bulkhead fitting at the bottom of the falls.

Some questions/thoughts I had:
- How critical is a UV filter to a pond this size? If it’s not critical, maybe i can just bypass all the valves and re-plumb to run from the busted joint directly into the bottom of the falls?
- I don’t know why the outflow from the UV went through flexi hosing into the top of the falls - it is not the most visually appealing aspect of the pond (usually I hide it behind plants) and In order to use the Matala mats I have in the falls, i have to wedge the hose down between mat and walls
- if the UV is worth keeping, any tips on re-plumbing this gap?

It’s probably worth noting that my theory on how this joint got “insufficiently deep” is that we have a redbud tree next to the pond that was probably a small sapling when we moved in, and now has 9ish years of growth on it...I suspect that over time, the tree’s roots/growth slowly pushed aside the PVC that’s running from the skimmer, making it curve slightly and pull out of that joint.

Also probably worth mentioning that while I have zero experience working with PVC, I am pretty handy and am very much up to the challenge of fixing this myself.

Thanks in advance!

 

[Mmathis]

Without claiming to be an expert, I have played around with PVC. Do you know if any of the joins had a PVC solvent used to permanently attach them? I would almost assume not, though, or you wouldn’t be where you are. Personally, I like to solvent-weld pieces like that, but I am in the Southern US, so freezing and heaving aren’t problems here. I don’t know how other folks do it — that’s just me.

Can you completely pull pipe B out of the other end? If so, I would do that and replace it with another piece, cut slightly longer than the original. Dry-fit all joins to be sure the length is correct. Clean the PVC well where there will be joins in the old and new pieces. If you are going to use a solvent-weld, I would find one made specifically for use in wet conditions. The kind that Home Depot carries is in a blue container. Personally, again, I like to use the stuff you put on before you apply the cement — just helps make a better bond. Etc. for the rest of the PVC process. If you aren’t going to solvent-weld the pieces back, then just be sure all the ends are clean and fit well before you attach them.

Maybe someone else can give better or different help.

Great detective work! Many people never can find their leaks!

 

[poconojoe]

PVC is super easy to work with and the fittings are super cheap as well.
Get a coupling that size, a short piece of schedule 40 PVC that size, a small can of pvc primer and a small can of PVC glue.
If necessary, dig the hole out a bit more for room to work and spread the pipe. Cut the pipe you have labeled "B" in the center with a hacksaw or sawzall. Trim the burrs with a utility knife or sandpaper. Dry fit the coupling and a cut a short piece of straight pipe to meet that tee fitting marked "A". Once you're satisfied with the fit, pull it apart and brush primer on both sides of all the joints. The primer cleans and primes the pipe. When that drys, get ready for the glue. This stuff sets up pretty quick, maybe 20-30 seconds so you have to be quick. Glue one joint at a time since you are inexperienced and you will be OK. When you glue a joint, brush the glue on both sides of the joint and push them together quickly. Then when you fit it together, do a quick twist to make sure the glue has spread and the fittings have bottomed out. Hold it together for maybe 30 seconds so it doesn't expand apart. This can happen sometimes.
I hope this doesn't seem complicated, because it's not.

 

[poconojoe]

If it's only the one joint that has separated, use a coupling, like I stated in my first post. If both joints came loose, you won't need a coupling, just a piece of straight pipe.

 

[IPA]

I think it broke from the freeze thaw over many years; probably wasn’t a good solvent weld to begin with, guessing there is a piece still glued in the fitting... or ... it was never solvent welded. Schedule 40, the white stuff isn’t really made for freezing and I’d guess your freeze line is about 2 foot or more where you live. They have different “schedules” depending on the application. PVC is relatively cheap as stated and easy to work with. I use the blue cement just because I’ve watched way too many Pond Digger episodes, haha.

 

[poconojoe]

Schedule 40 is the standard one. There is the heavier walled schedule 80, but you don't need that.
That joint probably wasn't glued well. Those glue joints practically last forever. I've never had one fail.
Just as a note if you plan on working with PVC in the future:
Dry fit your project and before you take each joint apart to glue it, use a sharpie to draw an orientation line across each joint. This way you know the exact orientation of each fitting. This is imperative since many of your fittings may face a strange angle or twist in a peculiar direction. Only prime and glue one joint at a time so you don't lose the configuration of pipe run.
I actually enjoy working with the stuff. There are so many fittings. It's like building a puzzle. 90 degrees, sweep (longer) 90 degrees, street elbows, reducers, couplings, 45 degrees, tees, X fittings, female threaded adapters, male threaded adapters, threaded caps, and so many more. They are very cheap too. Some under a dollar and the more complicated ones a mere few dollars. (Depending on pipe diameter)

 

[Lisak1]

I've had glued joints let loose. If you put enough pressure on them over time, they will fail. I would guess you have had some settling that just caused your pieces to let loose. As others have already said, if you need more pipe to work with, it's cheap. Make sure you get everything clean and dry before you try to glue it and you should be good for another 20 years. As far as pond plumbing problems go, this one isn't so bad!

 

[clark kent]

If glued PVC joints are done right, they are stronger than the pipe and fittings that they join. You have cut, clean, and test fit the pipe and fittings, prime the joints, use the correct glue, fit the glued parts together in proper alignment in a timely manner, and hold them together until the glue sets. There are dozens of good videos on youboob on how to do a good PVC glue joint. The pipe and fittings are cheap enough that you can glue a few pieces of pipe and fittings together just for practice.

BTW, the proper term is "solvent welding."

 

[Mmathis]

@clark kent. LOL, it drives my husband crazy when I say “solvent weld” instead of glue. He thinks I’m being a PVC snob,

 

[poconojoe]

@clark kent. LOL, it drives my husband crazy when I say “solvent weld” instead of glue. He thinks I’m being a PVC snob,

Ha! Solvent weld.... I've been working with PVC for years, both plumbing and electrical and have never heard that term! I guess I wasn't taught the correct terminology! 62 years old and Still learning...