Pond Plumbing

[sburtchin]

I live in Ohio. Temps of -10 F to -20 F are typical. My local zoning code has no restrictions regarding garden ponds. This will not be a swimmig pond. The pond plumbing will be completely separate from the house plumbing. It will contain (decorative) fish and other animals. Most people use the SCH 40 PVC. Some of the plumbing will be burried below the frost line, some below water, and some will be exposed to the weather.

Do the codes make any restictions on what can be used for this application?

Are there PVC products that can withstand freezing? Something else?

 

[Neo_Ocelot]

Sorry can't help with codes, but I am curious what "other animals" will be used in the pond?

 

[Chris]

Probably no codes to follow for pond plumbing.

 

[stevemachine]

No codes for pond plumbing. As far as freezing. Wirsbo is more forgiving and pvc will crack if its full of water and freezes.

 

[sburtchin]

Sorry can't help with codes, but I am curious what "other animals" will be used in the pond?

Frogs, turtles. In addition, birds, squirrels, rabbits, opossums, and raccoons make daily visits. On rare occasions cats and dogs get a drink. Everybody likes water.

No codes for pond plumbing. As far as freezing. Wirsbo is more forgiving and pvc will crack if its full of water and freezes.

What is "Wirsbo"?

I need to create a 35' run of 2" PVC below the frost line. Alongside will be conduit for the pump and other electricals. My main concern is where it enters and leaves the ground. The rest can be drained during the winter, but if I choose to keep it running, it can freeze in a power outage.

Electrical will be strictly to code for safety, but for the water most people do whatever will work. The maximum possible pressure would be about a 20' head of water - whatever that works out to in psi. So with no codes to follow, I'm back to seeing what I can salvage from my pipe collection (See my other thread: Plastic Pipe Compatibility). My main concerns would be to not leak toxins into the water, and to not create a situation that can lead to a future leak. I have a 10' section of 2" conduit, a 6' section of 2" ABS "DWV", and some white "Non-Pressure" and white "DWV" I could use. What do you know about the chemistry of these products, pressure limits, and compatability of these products with the SCH 40 PVC? Will I need to use pressure fittings, or will the DWV fittings be OK in this application?

I do not want to take any chances with that buried section.

 

[stevemachine]

20' is about 8 psi. I would not suggest any dwv products. Wirsbo is flexible and has a memory. Basically it freeze and thaw and the pipe should never crack. Fittings however are different. You need to get a tool to use it. I'd suggest sched 40 pvc. Which is rated far beyond any pressure you will use it for. Its eiter 125 or 150 psi rating. Dwv is rated for no more than 5 psi at best. Sched 40 pvc is relatively cheap and easy to use so avoid any dwv. When you do the pvc make sure you're gluing above 35 F otherwise glue doesnt cure properly. Give the glue a good two hours above this temp to fully cure and then you are set.

 

[stevemachine]

Wirsbo is good but the tool is about 200 some bucks. Its easy to run and size goes up to 1" that is readily available but doesnt sound like its the pipe you need in this situation

 

[sburtchin]

20' is about 8 psi. . . . Dwv is rated for no more than 5 psi at best. . . . Wirsbo . . . goes up to 1" that is readily available but doesnt sound like its the pipe you need in this situation

OK, it should be all pressure rated PVC for the below ground plumbing. At the low pressures produced by pond pumps, loss due to flow resistance becomes very significant. For the long underground run I know the 2" PVC is fairly cheap. I might use 2-1/2" if the price difference is not too great. Over short distances much smaller pipe can be used. Can the Wirsbo be used with barbed fittings and hose clamps? Is there a limit to the freeze/thaw cycles (or how many years) it can withstand?

Is it possible to create a fail-safe configuration that would automatically drain the above ground sections in the event of a power outage? The plumbing here would essentially resemble the following diagram where the equal signs represent ground level and the asterisks represent the pipe (ignore the dots):

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* * . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* . discharge
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* . . . . . . . .
. . . .* * * *. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . .
. . . .* . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* . . . . . . . . .
====*====*===================================*===========
. . . .* . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . .
. . . .* . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . .
. . pump . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . .
. . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . .
. . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . .
. . . . . . . . * * * * * * * * * * * * * * * * * * * * * * * * . . . . . . . . . .

Can the pressure generated inside a frozen pipe be counterbalanced by a suitable amount of reinforcement? What would the pressure rating have to be?

 

[stevemachine]

Agreed with the pvc, upping the sizes are a good idea on long runs. It'd be a shame if its all put in and you dont get the flow you want because of the flow restriction on 2" vs 2 1/2 or 3". Roughly how long is your longest run and what are the specs on your pump.

Wirsbo can thaw and freeze as much as you want but the brass or plastic fittings you use are a different story. I suppose if you had no fittings underground where it cant be drained would be the solution if thats possible. Ive never tried that so im not too sure but i would imagine low pressure like that it would hold up just fine. Definitely not installed as its designed but I would test a small portion before doing the whole thing like that.

If the pump doesnt have a check valve the water shouldnt stay in the underground portion that is vertical supposing the power goes out. It will just drain back into the pond.

No way to counterbalance the freezing with support. Its about volume not pressure. Pipe full of water is max amount of volume it can hold, now when it freezes it expands 8%

 

[stevemachine]

Not sure if im seeing your pic right but if there are any horizontal runs grade them to a low point and put a drain there or you can grade it all back to the pump ex. Pump is low point so slope all discharge piping slightly uphill so when power goes out or what not itll all drain back to pump w/o check valve

 

[sburtchin]

Adding some more information to my diagram: The pump sits within a covered sump that the pond drains into (this is an oversimplification - the plumbing in there is somewhat protected). There is a very short run that is exposed before plunging into the ground. This is followed by a 28 foot run buried below the frost line. The flow then rises vertically and is discharged at the head of the stream feeding the pond (the stream head is supported by two retaining walls - not shown). An electrical conduit runs parallel with the buried plumbing.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* *discharge
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* . about 30"
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * above grade
. . . . 24" run max . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . .
. . . .* * * * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* . . . . . . . . .
=| . .* . |= *====== finished grade =================*============
. |---*--| . * . . ---water level--- about 6" below grade . . * . . . . . . . . . .
. | . .* . | . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* . . . . . . . . . .
. | pump | . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .* . . . . . . . . . .
. +------+. * . . frost line - about 30" below grade . . . . . . * . . . . . . . . . .
. . sump . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . . . . . . . . .
. . . . . . . . * * * * * * * * * * * * * * * * * * * * * * * * . . . . . . . . . .
. . . . . . . . . . . . 28' run @ 36" below grade . . . . . . . . . . . . . . . . . . . . . .

A heater can be placed within the sump providing several hours protection without power for the plumbing contained there. At risk is the short run before entering the ground, the vertical sections entering and leaving the ground, and the exposed section just before the discharge.

I see what you are saying, that if all horizontal sections have a gentle slope back to the pump with no place for water to pool, then the pipe would drain itself in the absence of any check valve. That solution (actually the one most frequently used [with nearly straight streams]) has its problems too. A much longer run would be required to avoid stream crossings (my stream will not be straight), digging to move ornamental plants and trees is frequent in this area, and I would have to go through the base of two retaining walls.

The size of pump required depends on the size and number of fish and other animals living in the pond, the filtration system, water temperature and many other factors. The flow must be sufficient to allow the good bacteria to convert all biological waste into harmless chemicals. For my size pond a 1000 gallons per hour pump would be sufficient except for extreme fish loads. I may be able to get by with much less.

I have two pumps. The G210 for 24/7 use and the G535 for extra effects or continuous use if the smaller pump is insufficient.

The G210 has a maximum lift of 7.4 ft. and will deliver 210 gph @ 1', 170 gph @ 2', 119 gph @ 4' and 61 gph @ 6'.

The G535 has a maximum lift of 12 ft. and will deliver 535 gph @ 1', 502 gph @ 2', 434 gph @ 4' , 356 gph @ 6', 282 gph @ 8' and 175 gph @ 10'.

Bigger pumps generally have greater lift and cost more to operate. Pumps must run continuously in warm weather to prevent growth of septic bacteria.

Wirsbo can thaw and freeze as much as you want but the brass or plastic fittings you use are a different story. I suppose if you had no fittings underground where it cant be drained would be the solution if thats possible. Ive never tried that so im not too sure but i would imagine low pressure like that it would hold up just fine. Definitely not installed as its designed but I would test a small portion before doing the whole thing like that.

Not sure what you mean by the low pressure being a factor to hold up longer, and what are you suggesting that I test?

 

[stevemachine]

Ok im getting a better visual of what you have now. One thing i can suggest on the runs that are prone to freezing is a heat trace. They make heat traces that people put in their gutters, which would essentially make these water proof. Make sure its on a gfi circuit, hope this is an option otherwise all you can do is put a drain on low points and leave access to drain the pipe. No other way around it.

What size of inlet is on the pump? Im thinking it cant hurt to upsize one size, to ensure you are getting the volume you require due to these pumps being high volume pumps but again that's up to your judgement, thats just my two cents.

For the wirsbo if installed as per manufacturer specs is rated to 100 psi. Typically used for domestic water and hot water heating in residential applications. You would not be installing it as per manufacturer specs by using hose clamps and barbed fittings which are much different from wirsbo fittings. You can do a few things if you would like to try wirsbo. You can get a 20' piece if wirsbo, buy a plug and a hose clamp and cap one end fill it full of water. If you have some where to stretch this out 20' vertically let it sit for a bit and you will have your answer as to whether or not wirsbo pipe used with hose clamps and barbed fittings will hold up to 20' of head pressure rather than install wirsbo on your small runs and then you curse me out because those hose clamps and barbed fittings leak like a siph. I think they'll hold up but not 100% sure so thats why i suggest test it first. Another option is go to your nearest supply house and get pex fittings and hose clamps to seal it with pex fittings. I suggest pex fittings because i know that pex fittings with crimp rings do work on wirsbo pipe and hose clamps essentially do the same thing as a pex crimp ring.

 

[sburtchin]

There will be GFCI outlets at both ends of the underground section, so the heat trace is insurance as long as there is not an extended outage. The "finished grade" in the diagram is about 12" above the level of the surrounding yard, so the low point (buried section) is about 24" below that. The land is really flat here. I would have to do some surveying to see if it's possible or practical to drain it into the yard. Same restriction if I wanted to siphon it out of there.

I have seen demonstrations of how the momentum of water flowing through a double trap can siphon both traps dry. I was hoping there might be some configuration that could siphon the water from the buried pipe. This leaves me with a few options besides making the exposed sections freeze tolerant with Wirsbo or heat trace.

OTHER OPTIONS: I could displace the water with ambient air or compressed air (not sure how that would work on an automated basis). I could siphon it into the yard (might not be practical or possible). I could drain it into the yard (same restrictions) while temperatures are above freezing. I could hack together a jet pump out of PVC to drain it. I could leach it near the house foundation (the water table might be too high away from the house). I could drain it into the basement. At least a couple of these solutions require a valve to be buried. I'm open for suggestions on other methods.

The outlet on the large pump is 9/16" ID with a MNPT thread (size not specified). The outlet on the small pump (in use) is about 7/16" ID (just a guess) with a 1/4" MNPT thread. The 535 gph pump recommends 3/4" ID tubing and the 210 gph pump recommends 1/2" id tubing. I would guess a 1000 gph pump would recommend 1" ID tubing being roughly double the cross section of 3/4". Over short runs with these sizes the loss is hardly noticeable. A 30' run of 1/2" ID hose connected to the 210 gph pump reduces the output severely.

I have a short piece of pex which was explained to me as having limited freeze tolerance. I didn't know if the Wirsbo was just the next generation of the pex, or altogether different. I could get some Wirsbo and cap both ends of a short section and put it in my freezer. That should generate the most pressure it would likely be exposed to.

One more concern: If Wirsbo is used everywhere above the frost line, What happens to the pressure inside the buried section as the freeze travels downward? Do I need a pressure relief to keep the PVC from bursting?

 

[stevemachine]

There will be GFCI outlets at both ends of the underground section, so the heat trace is insurance as long as there is not an extended outage. The "finished grade" in the diagram is about 12" above the level of the surrounding yard, so the low point (buried section) is about 24" below that. The land is really flat here. I would have to do some surveying to see if it's possible or practical to drain it into the yard. Same restriction if I wanted to siphon it out of there.

I have seen demonstrations of how the momentum of water flowing through a double trap can siphon both traps dry. I was hoping there might be some configuration that could siphon the water from the buried pipe. This leaves me with a few options besides making the exposed sections freeze tolerant with Wirsbo or heat trace.

OTHER OPTIONS: I could displace the water with ambient air or compressed air (not sure how that would work on an automated basis). I could siphon it into the yard (might not be practical or possible). I could drain it into the yard (same restrictions) while temperatures are above freezing. I could hack together a jet pump out of PVC to drain it. I could leach it near the house foundation (the water table might be too high away from the house). I could drain it into the basement. At least a couple of these solutions require a valve to be buried. I'm open for suggestions on other methods.

The outlet on the large pump is 9/16" ID with a MNPT thread (size not specified). The outlet on the small pump (in use) is about 7/16" ID (just a guess) with a 1/4" MNPT thread. The 535 gph pump recommends 3/4" ID tubing and the 210 gph pump recommends 1/2" id tubing. I would guess a 1000 gph pump would recommend 1" ID tubing being roughly double the cross section of 3/4". Over short runs with these sizes the loss is hardly noticeable. A 30' run of 1/2" ID hose connected to the 210 gph pump reduces the output severely.

I have a short piece of pex which was explained to me as having limited freeze tolerance. I didn't know if the Wirsbo was just the next generation of the pex, or altogether different. I could get some Wirsbo and cap both ends of a short section and put it in my freezer. That should generate the most pressure it would likely be exposed to.

One more concern: If Wirsbo is used everywhere above the frost line, What happens to the pressure inside the buried section as the freeze travels downward? Do I need a pressure relief to keep the PVC from bursting?

Definitely do a heat trace, extra insurance is always good. See what you figure as far as the yard goes. Putting a drain in and grading pipe is the best option. Hell even if the pipe is level it'll still empty the pipe as long as there's no high point anywhere. Principal being that as long as pipe isn't completely full the water has room to expand now.

Siphonage i don't think is really practical in a pressure piping situation based on the principal of Siphonage i don't feel it would work.

Now those are some good ideas. Compressed air is usually what people use to blow out their domestic supply on seasonal properties. Still need a drain though and a point in which to fill the line with compressed air. Out of those suggestions i like the compressed air the most. Its probably the easiest solution but thats just my two cents.

Agreed with your logic on line sizing with pumps, sounds about right to me.

Wirsbo is a variation of pex with a memory and more flexibility. Also lifetime warranty if installed to manufacturers specs. Pex freezes it will crack. Wirsbo freezes it will stretch. If you do cap both ends full of water and toss it in the freezer it will hold up just fine. They showed us that experiment in school and thats what drew me to recommend this to you.

How i see it is that if you add wirsbo to your runs that act kind of like an expansion tank would in a heating system. Since wirsbo has room for expansion in theory the water that freezes and expands should go to those wirsbo sections because thats where there is some give. I would suggest almost adding a tee somewhere in the vertical and put chunk of wirsbo coming out of the tee as long as reasonably practical and that gives your system some room for expansion. That way its another fail safe

 

[sburtchin]

Definitely do a heat trace, extra insurance is always good. See what you figure as far as the yard goes. Putting a drain in and grading pipe is the best option. Hell even if the pipe is level it'll still empty the pipe as long as there's no high point anywhere. Principal being that as long as pipe isn't completely full the water has room to expand now.

You convinced me. Any Winter situation that leaves water in the pipe should have the extra insurance. If I could grade the drain pipe, that would be great. Very optimistically I might be able to have a 6" fall on a 70' run, the last 20' of which would be very close to the surface. I can see the ground heave more than 2" around the foundation of a small building in that low area during the coldest weather. The high spot can't be more than the diameter of the pipe from the low point, so with any small diameter drain pipe this becomes very challenging. Alternatively, I could use a freeze tolerant tubing, like is used for lawn sprinkler systems (assuming I actually have at least a 24" drop in grade over that 70'). With either of those solutions I would have to get it drained before the ground freezes. I guess the valve would have to be at the far end of the drain pipe. If any part of the drain pipe fails, the repair situation would be catastrophic.

Siphonage i don't think is really practical in a pressure piping situation based on the principal of Siphonage i don't feel it would work.

Right, I am at a loss to see how this might be configured to happen automatically.

Now those are some good ideas. Compressed air is usually what people use to blow out their domestic supply on seasonal properties. Still need a drain though and a point in which to fill the line with compressed air. Out of those suggestions i like the compressed air the most. Its probably the easiest solution but thats just my two cents.

I was thinking of compressed air as an alternative to putting in a drain. The air would be inserted where the pump is and 'hopefully' blow out enough water at the other end. Some experimentation is necessary. It doesn't matter if the section below the frost line remains full of water.

How i see it is that if you add wirsbo to your runs that act kind of like an expansion tank would in a heating system. Since wirsbo has room for expansion in theory the water that freezes and expands should go to those wirsbo sections because thats where there is some give. I would suggest almost adding a tee somewhere in the vertical and put chunk of wirsbo coming out of the tee as long as reasonably practical and that gives your system some room for expansion. That way its another fail safe

I would guess that the Wirsbo does not expand much at its rated pressure of 100 psi. Then when it freezes the pressure becomes much greater in order to stretch the pipe to an 8% greater volume. If Wirsbo is used as an expansion tank, the critical factor would be how much it can expand before the pressure inside exceeds the pressure rating of the PVC pipe. If I'm reading you right, the Wirsbo used for expansion would need to be buried below the frost line, and probably have some physical protection to prevent the surrounding soil from pushing against it.

The solutions I am leaning toward are: using compressed air to blow out enough water, using a jet pump (which would be especially nice if the pond pump could provide sufficient pressure), adding an access plug to stick in a manual siphon tube, putting a drain valve in the basement, and leaching the drain water near the house foundation. The first two require some experimentation.

 

[stevemachine]

You convinced me. Any Winter situation that leaves water in the pipe should have the extra insurance. If I could grade the drain pipe, that would be great. Very optimistically I might be able to have a 6" fall on a 70' run, the last 20' of which would be very close to the surface. I can see the ground heave more than 2" around the foundation of a small building in that low area during the coldest weather. The high spot can't be more than the diameter of the pipe from the low point, so with any small diameter drain pipe this becomes very challenging. Alternatively, I could use a freeze tolerant tubing, like is used for lawn sprinkler systems (assuming I actually have at least a 24" drop in grade over that 70'). With either of those solutions I would have to get it drained before the ground freezes. I guess the valve would have to be at the far end of the drain pipe. If any part of the drain pipe fails, the repair situation would be catastrophic.

Right, I am at a loss to see how this might be configured to happen automatically.

I was thinking of compressed air as an alternative to putting in a drain. The air would be inserted where the pump is and 'hopefully' blow out enough water at the other end. Some experimentation is necessary. It doesn't matter if the section below the frost line remains full of water.

I would guess that the Wirsbo does not expand much at its rated pressure of 100 psi. Then when it freezes the pressure becomes much greater in order to stretch the pipe to an 8% greater volume. If Wirsbo is used as an expansion tank, the critical factor would be how much it can expand before the pressure inside exceeds the pressure rating of the PVC pipe. If I'm reading you right, the Wirsbo used for expansion would need to be buried below the frost line, and probably have some physical protection to prevent the surrounding soil from pushing against it.

The solutions I am leaning toward are: using compressed air to blow out enough water, using a jet pump (which would be especially nice if the pond pump could provide sufficient pressure), adding an access plug to stick in a manual siphon tube, putting a drain valve in the basement, and leaching the drain water near the house foundation. The first two require some experimentation.

If you got even 4" over 70ft thats enough. You hardly need grade, way less than typical drainage. If you got 1/16" per ft that's enough in my opinion to drain that pipe down.

Compressed air could be done that way of you feel its an option. Definitely some experimenting required. Now as far as a jet pump, pumps require water to cool the impellers. So if you're not using water the jet pump isn't an option. Which the object being to rid the system of water doesn't sound like it'll work.

Regardless of pressure the pipe flexibility isn't dependent on pressure. That pipe is full of water at 2 psi or at 100 psi so pressure shouldn't make a difference. To a certain point amount of expansion depends on how much pipe is installed. Again i'm just bouncing ideas here, this is something that is not traditional plumbing so the wirsbo idea is a creative way that i can think that will give room for expansion.

I like compressed air. Like i said people do this all the time for their cabins and seasonal properties. Requires experimentation for sure but if grade isnt as plausible this is you're second best option next to grading pipe.

 

[sburtchin]

The biggest drawbacks I see to a drain pipe graded from the lowest point is that an additional 70' trench has to be dug to the low point of the yard, the last 20' would be close to the surface and subject to physical damage, and if I don't get it drained before the ground freezes the slow moving drain water could freeze at the exit point creating an ice plug.

Doing some research, my use of the term "jet pump" was a bit misguided. What I meant to describe would be a variation on the deep well jet pump setup. A custom built ejector package would be placed at the lowest point in the plumbing. The suction side would be vented to the atmosphere rather than to the inlet of the pump. The drive side would be connected to the 'pump' which could be either a garden hose or the outlet from the pond pump (provided it can generate enough pressure). For practicality, the ejector package must provide at least 42" of lift. Some experimentation required.

What do you think of leaching the water near the house foundation? I'm thinking the perimeter tile should easily carry away a few gallons at most. The basement walls are poured concrete. Con: Drain valve would be 36" below finished grade.

 

[stevemachine]

Ok if you monitor the jet pump set up i can see the logic and that sounds like it would work.

Weeping tile can handle that for sure. But i see the issue with the valve being 36" down.

Now its to a bit of experimentation and good judgement i think i've given you all the facts for you to make a good decision now

 

[sburtchin]

Now its to a bit of experimentation and good judgement i think i've given you all the facts for you to make a good decision now

Thanks for all the attention you have given to this non-standard plumbing project. I will post back with details of my final design when I have it.

 

[stevemachine]

No worries happy to help and let me know how it goes