# What's the rule for PVC pipe size vs flow?



## jmr106 (Nov 27, 2016)

In  the near future, I'm going to be installing a large sump  basin (50 to 70 gallons or so) in the  crawlspace with two new pumps that are more efficient and will kick out even more water with little noise.  Each pump will have its own pipe with a  roughly 7' initial head, then  both will run about 5 feet horizontal and go out of the crawlspace to the outside,  make a 90 degree turn and somewhere around that area just outside of the  house it will split into a single PVC pipe to continue the 20-25ft run  out into the back yard. The pumps can handle it and are designed for up to a 25ft head with no problem. 

I'm doing this joining of the pipes outside  because if the two pipes joined a single larger pipe inside of the crawlspace and something happened to the larger main pipe, that would be a big failure.  However, with two separate pipes going outside, there is a backup and  it would at least get the water outside of the house even if the split  to the large pipe came loose outside of the house. I just like to plan  ahead of time.  

I talked to the guy at the place where I'll be buying the pumps. He told  me, "I would suggest that you tie those two discharge pipes to a minimum 2-1/2" or even 3" PVC pipe for maximum performance. As long as  the horizontal pumping distance is not extreme, you will be fine."  Is it really that simple - doubling the pipe size to whatever the main pipe is to be? My research hasn't been coming up with that.

One will be primary and one for backup. Each pump can kick out about  3,330GPH, or roughly 55GPM. In the rare crazy rain event where both need to come on and 110GPM is going through one pipe, I want to make sure it  is big enough. However, apparently a pipe that is too big has the opposite effect - losing pressure to push the water out fast enough and with enough force.

Suggestions? I have done Google searches and such, but there always seems to be conflicting information. One place says x thousands of gallons should flow through x size pipe, and then another place says something totally different. I want maximum flow rate for each pump without losing the pressure. 

I really need to angle the entire horizontal pipe run (the part that runs along the ground) a little bit somehow, so that nothing freezes in the pipe during the winter discharges.


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## frodo (Nov 27, 2016)

each  gpm = 2 fu   both pumps running = 220 fu

220 fu minimm size discharge is 4'' both pumps tied in

3'' minumum  seperate


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## jmr106 (Nov 27, 2016)

frodo said:


> sump pump or effluent pump
> 
> storm water or sewage



Sump pumps. After a lot of research, I'm going with dual 1/3HP Ion Storm Pros. Stainless steel. Total 4.5 running amps each, but kicks out as much as some 1/2HP pumps that use way more amps. It utilizes a digital level control, solid state with no moving parts to wear out. I'll either elevate one above the other somehow as strictly a backup pump sitting on something else in the basin. Or maybe I'll use the digital on one and the float switch on the other for higher volume.













Impeccable reviews and pretty much special order pumps.

I'm technically going to be using a sewage basin for the sump basin, because the regular sump basins aren't typically made to that size or they want $500 for an equivalently-sized sump basin that looks virtually the same as the sewage basin. 

Storm water.


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## frodo (Nov 27, 2016)

make sure it seals tight, it is a blooming high way for crawly things


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## jmr106 (Nov 27, 2016)

frodo said:


> make sure it seals tight, it is a blooming high way for crawly things



The sump pit itself? I'm planning to get the matching lid with the custom holes with rubber gaskets around them, a hole for electrical, etc. Trying to figure out if there is some kind of flap that I could put on the end of the discharge pipe that would close down and prevent any critters from getting into the pipe when it isn't discharging. Sort of like what we have on the dryer vent. 

Are the gate valves simply there as a means to keep any water in the pipe above from getting everywhere if a pump needed to be changed out or one side turned off for some reason?

Is a weep hole really necessary? I have been reading a lot about people drilling a weep hole in the pipe just above where it attaches to the pump to prevent some sort of air lock, but my current pipes do not have that. Haven't had any air lock issues on either pedestal pump.


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## frodo (Nov 27, 2016)

use a 4'' pvc backwater valve

code calls for the valve to be installed,,, 

weep hole,   do what the manufacture of the pump requires,  some call for it others do not


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## frodo (Nov 27, 2016)

you NEED to wire your pumps to lead/lag

pump 1 comes on,  pump 2 will come on if high water is detected

then the next cycle

pump 2 comes on, pump 1 will come on if high water is detected

then next cycle

pump 1 on  pump 2 if needed

etc etc...

you do NOT want one pump sitting there not being used


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## jmr106 (Nov 27, 2016)

frodo said:


> you NEED to wire your pumps to lead/lag
> 
> pump 1 comes on,  pump 2 will come on if high water is detected
> 
> ...




There are some pump controllers that I have seen that do this. That's about the only way that I know of to do that. Unless we're having a really rainy season, the pumps don't get a lot of continual use. Our issue is more so...when it decides to rain for 2-4 days straight. The pumps might come on for a day or two after that, maybe averaging 30 gallons per minute coming in when things have calmed down. Or a random thunderstorm that dumps so much water at one time that I get 80-100 gallons per minute flowing in for maybe 20-30 minutes and then it goes away. I'm going to be using a basin surrounded by gravel. Due to the size of the basin that I'll be getting, I'll have to punch holes in it myself. I'm trying to figure out a way to have holes in the basin so that water will flow in and the basin won't push up, but also...figuring out how the heck I would test it if any water that you poured in would seep out of the holes into surrounding gravel. Both of the pumps will need to be tested regularly since it doesn't get water flow all of the time. I could leave some of the bottom of the basin solid without holes in it, but I'd have to make sure that it doesn't cause it to float.


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## frodo (Nov 27, 2016)

not following....are you installing an area drain   or a sump pit

if its a sump pit,  the tank sits below the ground, the drainage pipe enters it at about the top 1/4 area 

https://agrimart.net/4-poly-bulkhead-fitting-tf400/?gclid=Cj0KEQiAperBBRDfuMf72sr56fIBEiQAPFXszUEItR4FSJy1GgS0wRmdN8NNIuehIkYsSTp63oceV50aAk3_8P8HAQ

look around, google you can find one cheaper


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## jmr106 (Nov 27, 2016)

I'm tackling an issue in an icky crawlspace that I've had other threads about. Its a dug-out portion of a crawlspace approximately 15'L x 4'W x 3'H with a retaining wall around it. 2-3 days of rain and the rain comes in through the wall from seemingly all sides. Suspected that an old septic tank about 8-10 feet outside of the house (which has been found and filled with dirt since the last rainfall that triggered the pumps) may had something to do with it, as a potential "water flow hole" was found in a corner of the outside of the wall months ago. Got about 2.5 inches of rain coming up over the next few days, so if it triggers the pump, I'm going to see if a lot of the water was coming from the old septic tank that may have been filling and making its way to the crawlspace a few feet underground.

The only solution found after months of pondering and research was to fill that whole area with drainage gravel and install a big sump basin and strong pumps. The flow may be less now, but with a saturated ground when it rains, I still expect some to come in. So I'm installing a proper sump (which it doesn't have at the time) to deal with it.

So in this case, we're talking a ton of gravel all the way around and no sump pit. Just a basin. Water would come from all directions in the gravel, so a basin with holes around it is needed to let the water in. There is no proper water outlet pipe to connect to the basin, so I'm struggling to find a way to make a basin that won't float itself out of the gravel and yet will somehow allow me to keep a bit of water in it when I want to test the pumps. Otherwise, putting water in the basin with holes in it would make it just flow out into the surrounding gravel that the basin is in. I could leave maybe a foot or so of the bottom of the basin without holes in it, but the only concern with doing that is the potential for it to float. Of course, each pump is about 25+ pounds. I'll probably stick some kind of brick or something in there to elevate pump two so that it alternates somehow, or I'll get a pump controller of some sort. Working with the manufacturer on that currently to see what they recommend. Most basins are little and therefore the drawdown is about 6" to 10" max for the average pump. I'd prefer to pump out way more than that at once to prevent short cycling and just to keep up with any heavy water flow that it can get sometimes.


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## nealtw (Nov 27, 2016)

jmr106 said:


> I'm trying to figure out a way to have holes in the basin so that water will flow in and the basin won't push up, but also...figuring out how the heck I would test it if any water that you poured in would seep out of the holes into surrounding gravel. Both of the pumps will need to be tested regularly since it doesn't get water flow all of the time. I could leave some of the bottom of the basin solid without holes in it, but I'd have to make sure that it doesn't cause it to float.



Run a loop of perforated pipe around your pit close to floor level and have it enter the pump box after a back flow preventor, drill the rest of the holes in the sides above your start level. That way you could check run your test and insure there will always be water in the bottom so it can't float.

You are going to seal the pies in the lid, are you going to run a third pipe or hose to the outside for testing?


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## frodo (Nov 27, 2016)

my thoughts,   sounds like you need to build a pit,  the poly,  will keep the water from undermining the pit


the top, of the mesh would be the same elevation,  as dirt level of the area to be drained


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## frodo (Nov 27, 2016)

jmr106 said:


> I'm tackling an issue in an icky crawlspace that I've had other threads about. Its a dug-out portion of a crawlspace approximately 15'L x 4'W x 3'H with a retaining wall around it. 2-3 days of rain and the rain comes in through the wall from seemingly all sides. Suspected that an old septic tank about 8-10 feet outside of the house (which has been found and filled with dirt since the last rainfall that triggered the pumps) may had something to do with it, as a potential "water flow hole" was found in a corner of the outside of the wall months ago. Got about 2.5 inches of rain coming up over the next few days, so if it triggers the pump, I'm going to see if a lot of the water was coming from the old septic tank that may have been filling and making its way to the crawlspace a few feet underground.
> 
> The only solution found after months of pondering and research was to fill that whole area with drainage gravel and install a big sump basin and strong pumps. The flow may be less now, but with a saturated ground when it rains, I still expect some to come in. So I'm installing a proper sump (which it doesn't have at the time) to deal with it.
> 
> So in this case, we're talking a ton of gravel all the way around and NO sump pit. Just a basin. Water would come from all directions in the gravel, so a basin with holes around it is needed to let the water in. There is no proper water outlet pipe to connect to the basin, so I'm struggling to find a way to make a basin that won't float itself out of the gravel and yet will somehow allow me to keep a bit of water in it when I want to test the pumps. Otherwise, putting water in the basin with holes in it would make it just flow out into the surrounding gravel that the basin is in. I could leave maybe a foot or so of the bottom of the basin without holes in it, but the only concern with doing that is the potential for it to float. Of course, each pump is about 25+ pounds. I'll probably stick some kind of brick or something in there to elevate pump two so that it alternates somehow, or I'll get a pump controller of some sort. Working with the manufacturer on that currently to see what they recommend. Most basins are little and therefore the drawdown is about 6" to 10" max for the average pump. I'd prefer to pump out way more than that at once to prevent short cycling and just to keep up with any heavy water flow that it can get sometimes.


..........


hince the drawing


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## jmr106 (Nov 28, 2016)

So a basin itself in the gravel will probably float or move out of place?


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## frodo (Nov 29, 2016)

an area drain will catch surface water

a french drain collects  water below ground

a pit collects water from pipes

you have suggested you want to use a sump pump pit

and you have suggested using a basin

i do not know which you are actually going to use...

a basin, out of concrete will not float. IF  you use the poly apron to keep the water from under mining


if you use a pit  [store bought]    to collect surface water,  you will need to concrete a floor  

to channel the water to the pit

if you want to go cheap...use a 5 gallon bucket, drill holes in it

put the pump inn the bucket,   dig a hole


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## nealtw (Nov 29, 2016)

the bottom o the sump will be at the level of the old floor and with water coming in at floor level it's level should always be equal to the outside  water.
http://www.houserepairtalk.com/showthread.php?t=19909

If it does need concrete for weight, I think it is total cubic ft / 15 but boats with holes don't usually float.


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## jmr106 (Nov 29, 2016)

I could prod around on the floor in the hole with something and see if there is concrete underneath it. A lot of people seemed to establish somewhere back in that post (that Neal linked to) that the floor would have to have concrete or it would have fallen in long ago. That system is on a cement slab that weights quite a bit, then back in the corner, there's a 40 gallon water heater sitting on the dirt. That's probably pushing 500 pounds including the water. Beside where the pumps are, there is a cement ledge of some sort visible, as well.

The plan is already pretty much set in stone to hang the furnace from the floor and elevate said water heater. So basically I'd be left with the hole to figure out what to do with. The thing that I find irritating is that I'll likely only be able to get 30" of height for elevating that water heater due to the fact that they don't make them any shorter than about 46" to 48". I thought that lower capacity would make it a bit shorter, but they actually have some 30+ gallons pushing 54" tall and even taller than the 40 gallons. So, that's only about 30" or less max of gravel that I'd be able to put down. The only way to use the larger basins that I found (24"W x 36"L) would be to put gravel down into the existing sump hole and level it out so that only 6 inches of the basin would go down into it and rest on the gravel. Then the other 30 inches would be flush in the 30" of gravel and theoretically the lid of the basin would be flat or just slightly above the top of the gravel. Not sure how feasible that is going to be. We've pretty much covered the fact that an electric is out of the question. Not enough extra amps in the current breaker setup for that. External water heaters...I used to consider that, but I've had so many people tell me how unreliable they are and how often they break/need to be replaced that I don't want to even bother with one anymore. I'm beginning to think that I need to special order a shorter water heater (I've been told that there are some out there), but it might be fun trying to find someone willing to install it on-hand already.

I could use concrete to build a pit of some sort, and I get the general idea of your diagram. I just don't know how the heck to form such a shape with concrete without customizing a bunch of wood for a frame until it set. I'm pushing 45+ hours per week on average at work, so that extra time can be interesting to find. At the same time, whatever the solution is that will be used, I want to do it right the first time.


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## nealtw (Nov 29, 2016)

frodo said:


> rheem makes a 32'' tall lowboy
> 
> http://www.homedepot.com/p/Rheem-Performance-47-Gal-Short-6-Year-4500-4500-Watt-Elements-Electric-Water-Heater-with-Blanket-XE47SB06ST45U0/206188261?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-VF-PLA-D26P-WaterHeaters%7c&gclid=Cj0KEQiA6_TBBRDInaPjhcelt5oBEiQApPeTF5mRiLyD50uZDAeKf09PAoFj4AarP0xzjcUMp6jEaloaAgMX8P8HAQ&gclsrc=aw.ds



He needs gas, not enough power for electric.


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## jmr106 (Nov 29, 2016)

Yeah, I'd love to get one of those if it could handle it. Just don't want to throw another $2K to $3K out there for another breaker box installation just for that. Apparently they used to make these lowboys in natural gas, as well...but discontinued them because they weren't that efficient or something like that. I think it was something to do with the inside flue not being long enough to be efficient?

Basically from the floor to the floor joist is about 84". The estimated 30" elevation for the water heater is all that I could do if I got a water heater that was 46" or so tall. I factor in about 8" inches for the flue and such and a little distance from the joists per whatever the code requires in my state of Georgia. If I could find a 40" water heater...I'd have 36 inches (the whole wall is about 3 feet tall total) plus 8 inches extra for the flue or whatever. Then I could add more gravel or just not have to worry about it flooding even if the power/pumps went out. It would be elevated at the top of the wall where it wouldn't flood anyway. Ideally, that's my goal. Pumps would be just to keep it not so moist down there, in that case.


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## frodo (Nov 30, 2016)

back in the 50's.  they use to install water heaters. half in the attic. 

the top of the heater was in the attic,  the bottom was in a closet.

what do you have above you ?


I closet ?


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## jmr106 (Nov 30, 2016)

frodo said:


> back in the 50's.  they use to install water heaters. half in the attic.
> 
> the top of the heater was in the attic,  the bottom was in a closet.
> 
> ...




On one end of the hole, a bedroom and closet. The other end is the bathroom. The gas water heater was in the kitchen before my parents bought the house. The Federal Housing Authority told the previous owners no way, you're not selling until you move that water heater out of the house due to carbon monoxide dangers. The house next door apparently has it in the house still. Nobody was living there when it busted and it caused a disaster. So I'd never find anyone that would do such a thing legally now. So that's hon this hole and wall were built. They built the wall in a half-butt kind of way, too. 

I'm going to search around and see if I can special order one. The only issue might be finding a company willing to install it when I bought it online.


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## nealtw (Nov 30, 2016)

There are rules for in house use. There are placed in homes every day. There may have been other reasons for the need for it to be moved.
http://www.statewaterheaters.com/lit/im/res-gas/184115-000.pdf


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## jmr106 (Nov 30, 2016)

So I'm rather curious, now...

I'm just outside of Atlanta,  Georgia. We recently broke a 132-year record for the number of days  without measurable rain. We haven't had rain in about 50 days. We got  about 2.3 inches inches of rain yesterday within about an 8 hour time period. We got well over a half of an inch today in about 2-3 hours with some extreme  thunderstorms and downpours. Nearly 3 inches of rain in two days and I see absolutely no water flow in the floor of that hole, apart from the expected little bit that runs under the crawlspace door into the wall/hole, which I will address in the future. That was barely enough to put 2-3 inches of water in the existing pit in the floor and nowhere near close to triggering the pumps.

The difference between the last time we had a big rain event like this and this time was I filled in the 7.5'L x 4'W x 4.5'D old concrete septic tank that I finally found in the back yard a couple of months ago. Filled that with 7 cubic yards of fill dirt. That tank was not far from the back of the house. 

Would the drought have caused the dirt to soak up all of that rain and not flow into the crawlspace, or did my filling of the septic tank stop water flow coming from that hole behind the crawlspace wall? I'm kind of suspecting that water flowed out of that hole, but also around and in/through the wall blocks all the way around the wall. It is only washed out in that area. The rest of the sides have dirt all the way up to the top of the wall and no evidence of any water washing it out. The debris also isn't flowing into the hole through the wall. 

I have compiled this one large image with a description of each thing that I have observed. Am I thinking within reason here or should I still continue trying to fix this and assume that it might come back if it rained even more?

http://oi66.tinypic.com/34z0m4h.jpg


I expected to come home today and hear at least one pump coming on and go down to see water flowing across the floor. I see nothing. Do you think it just didn't rain enough or what? Usually that much rain seems to trigger the pumps and water would be coming out from every crack and hole all the way around the way around the wall that it could find. Mostly from behind that particular area with the hole in the dirt. Nada today. All of the rain is gone.


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## nealtw (Nov 30, 2016)

I guess time will tell.


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## jmr106 (Dec 1, 2016)

So if I theoretically removed the water heater and got an on-demand natural gas water heater mounted up higher than the crawlspace dirt (which is level with the ground outside) on some type of wall and got the furnace flipped sideways and hanging from the floor (should hang about as far down as the top of the wall,I would guess)....

What should be done with the big hole? Should I still put in gravel and new pumps with a proper outlet ran for the pumps?

Knock the wall down, remove it completely and fill it with screened fill dirt? Would that eliminate the underground water issue? Or, if it is still there, cause some sort or backup issue due to hydrostatic pressure? As far as I know, it couldn't come higher than the wall used to be and shouldn't come that high under dirt placed in the hole (taking it up to the level of the current crawlspace dirt) anyway. I could have any local company come and haul away the blocks of wall if I removed it.

Just trying to figure out the best solution to nip this in the bud and be done with the water in the crawlspace nonsense.


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## frodo (Dec 1, 2016)

if it was me. dig a hole,  set the pit,concrete the floor


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## jmr106 (Dec 1, 2016)

Well, part of a pit is already dug out technically where the pumps are. Pretty sure that's concrete under there. However, with the concrete on the floor...if I put that down on top of the floor, the water will basically run out of the wall and may or may not run on top of it. It may run over the top and also underneath it, sandwiching the water between the already-presumed concrete floor with a bit of dirt on top and the new concrete floor above it.

The same for the vapor barrier. It goes under the concrete, but if I put the vapor barrier down on top of already-existing concrete with dirt on top of it, then I'm putting another layer of cement on top and trapping water between both concrete floors in the hole. So I'd also have vapor barrier between the old concrete floor and the next concrete floor.


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## jmr106 (Dec 3, 2016)

................................moved for questions.


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## WyrTwister (Dec 16, 2016)

frodo said:


> you NEED to wire your pumps to lead/lag
> 
> pump 1 comes on,  pump 2 will come on if high water is detected
> 
> ...



You are essentially describing lead - lag control .

God bless
Wyr


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## nealtw (Dec 16, 2016)

WyrTwister said:


> You are essentially describing lead - lag control .
> 
> God bless
> Wyr



Lead , lag, doesn't work if you are just having a second pump for when your first pump can't keep up


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