Hello, my pool is near completion and the decking drainage lines are being dug in preparation for the decking to be laid. Unfortunately my builder did not lay the 4" drain line under the pool equipment plumping runs prior to them being set, and now he has a problem with dig room and can't go "under" all the plumbing already set as there is not enough space on the side-yard to run the drain line to the street.....and not enough slope if the line is on top. His solution is to place a catch basin just in front of the inaccessible dig spot (due to not enough slope) where the 4' line will run to a box, submerge a sump pump in this box, run a 2 inch line up and over the existing plumbing to another catch box, where it will then drain to the street. It is effectively a bridge for the water to go up and over to drain whenever the pool overflows. I'm not too excited about this and would like to hear some opinions about it. TIA
Drain line - decking question
- Thread starter Texas1
- Start date
- Jul 21, 2013
- 66,121
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
What will be the effect when the sump pump fails, which it will eventually do in some storm.
@jimmythegreek @Rich D what do you think?
@jimmythegreek @Rich D what do you think?
bligh
Silver Supporter
What's the change in grade elevation? If it's not all that much a straight 2" line w/a check valve should work. Although some area's require a 4 inch line, I see 2in lines around the hood, like the guy next door to me. What's being suggested sounds expensive.
Do you have any pics of the pool plumbing pipes in the area the drain needs to cross? How did he determine he could not go over or under the pool pipes? Did he actually dig them back up or is this something he is guessing at? Most builds do not stack the pool plumbing so you are probably only talking about 2-6" in hight and 4-5' in width , which should be manageable by either going over or under. We tunnel under utilities all the time. You just need to be sure to very careful and backfill with 3/4 clean stone so you do not create a sag in the pipe runs. Going under will be far less work and expense than installing what he is proposing. In addition I never like pumping drain water. Power outages are most likely to happen during storm events when you need the drainage the most as well as pump failures and maintenance and electrical costs. Gravity is cost and maintenance free for life.
Did they give you some exact numbers? Most people over estimate the slope requirements for drainage. .5% is more than enough in most cases. Could you clarify what you are draining? Is this a pool overflow or deck drain or both?
bligh
Silver Supporter
Most underground drainage and or dispersal piping require 2inch drop over 10 feet in length, so a 50ft run suggest a total of 10 inches, although the last 10 feet will clear without additional drop in elevation. Sorry no pics. The water going to waste on my pool is pumped, however I use to design surface and underground water capture and underground dispersal systems in a effort to keep some commercial customers parking lot dry after a unusually heavy rain or to move surface water away from a commercial building to keep the basement from flooding and the entrance door area dry. A drop of 2inches over 10ft in length works very well.
I would say that might be suggested or preferred in some cases but certainly not required.
2 inches in 10 ft = 1.6% . That is More than three times the slope that is required for this situation. Any drain layer that is worth his or her salt can easily get storm water to work at .5% in a 4 inch pipe. Typically the larger diameter pipe the flatter you can go. I have designed and built many drainage projects using 12-inch and even 6-inch pipe laid flat and they are still working fine to this day. A typical building perimeter drain is usually only 4-inch and it is laid flat and those runs can be hundreds of feet long.
The decking drains, pool overflow, and 2 house gutters will all tie to the same 4" pipe. The builder basically screwed up and didn't lay the decking drain line when they should have. Instead, they poured the 3' decking pad, set the equipment, ran all the pool plumbing (now sitting beside the pad), and have no room to dig around/under within this 5.5' wide space along side my house to lay the drain lines to the street. They should have laid the deck drain line at the same time they ran the plumbing lines to the equipment deck.....or under the equipment deck before they poured it.
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Wow.. that does look a bit tight. Is that a 4-inch pipe in the trench? What would that be for?
It's hard to judge the depths but those do look like they're fairly shallow. With the intended place to go be beside the air conditioner at the end? Is that a gas line I see down by the air conditioner? Are you absolutely sure you can't get one more pipe right up against the fence posts? I know it seems like a lot of work in the tight conditions but believe me, a gravity drain is far better than any pump. what kind of slope were they going to put on the pipe and how deep did it have to be in the area of the picture was taken?
I believe the bigger pipes are 3". I have 4 returns, the spa, bubbler line, and fountain line. Also a dedicated return for the glacier cooler. From looking at the foundation of the house and elevation to the street (about a 4-5' drop I'd guess over about 100') I think the decking line would have to go just under all the pool plumbing....or it should have gone under the equipment deck. Over the equipment plumbing is too flat to negative slope. No more room beside the fence. They basically locked themselves in the pocket between the equipment deck and fence. The gas line for the pool heater runs beside the A/C deck and the fence. Gas meter is on other size of the fence from the a/c.
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Are you using a laser or a builder's level to figure out these grades and slopes?
If the invert of your pipes at the beginning are approximately 1 foot below finish grade, then if you run the slope at .5% you can go 100 ft and drop 6 inches. So you will then be 18 inches below finish grade.
if you don't have one, I would get a laser level or a builder's site level. I would imagine your pool builder must have one. Then I would dig down by the pad and shoot an elevation on the top of the pool plumbing and then shoot an elevation of your lowest starting point and figure out your slope from there. You might be surprised how much pitch you actually have.
The drains all tie to the single run to the street. Its a curb cut out for the 4” pipe. Easily 5ft drop from the pool coping level to the street. They just don’t want dig around the plumbing and work at it.
They dont want to get in there and hand dig...being lazy it seems. I agree with Rich I'd shoot it amd see what you really have for pitch. You can compound pitch it too. Theres room in there. Zigzag, go over or under, whatever needed for gravity drain. I'd never rely on pumps for storm water in a good soaking you will never keep up with it.
Great. His original idea to fix his mistake was a terrible idea. He needs too do what ever is necessary to give you a gravity drain. He might now see the wisdom in always bedding plumbing and electric lines in sand. 4-6" of sand over those pipes would have made re-digging that line much easier. Not to mention if you ever need to get to a pipe for repair reasons. Do not let him cheap out on the pipe. You want a good quality pipe and be sure to put a clean out at major bends or in runs longer than 50'. Clean outs are there so you can snake the pipe if you ever get a blockage as well as to be able to quickly identify where a blockage is. For example you should definitely have one just before it goes into the town drainage. This will allow know if it is your line that is blocked or the towns line that is backing up. Sdr-35 would be what most would use for this, However because this line will be shallow and sitting on disturbed material, I would pay to upgrade to scdl 40. Then you know you have a bullet proof pipe. 4" sdr can also come warped from the supplier leading to sags in a low pitch pipe.
Ah okay I got it now.. sorry wasn't picking up what you were putting down. We really never put pipes right through the curb up in my neck of the woods..
