Main drain or no main drain....that is the question

dmacpharm

New member
Jul 17, 2019
2
Austin, Tx
Hello everyone. About to break ground on an in-ground pool (gunite, 18x35, max depth of 7', SWG). Builder is pushing hard for no main drain. Mainly due to the higher risk of leaks/cost to repari. He doesnt recommend but also wont charge me extra to install one either. So the question is do I have a main drain installed at no additional cost? Do the benefits out weigh the risks? Will it help with circulation in the deep end (7')?
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,426
Bedford, TX
If I had to do it over again, I would not get a main drain... I see no value in them...

If I were to ever drain my pool I sure would not be using my pool pump.

Thanks,

Jim R.
 
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kevinp768

Active member
Sep 30, 2018
30
Wichita KS
I'm on the other side of the fence myself. Having received torrential rains this season, I've enjoyed having the ability to lower my pool for significant storms and not worry about overflowing in the middle of the night, regardless of water height at the skimmer.
That being said, it does add another point of failure, but it was a risk I personally was willing to take.
Also, not having to drag out a sump pump every time I need to drain water is convenient as well.
 
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Newdude

Well-known member
Jun 16, 2019
1,095
NY
Me too. I drain both ways. Flip a lever when the pool is open and BOOM, easy peasy. When the pool is closed for the winter I have to drain a considerable amount from the rain and snow at least twice. I’m a worry-wart so I’m not ok just throwing the pump in the pool. So I rig up a redneck contraction to suspend the pump in the water so it doesn’t touch the liner. By the time I rig up a pipe across the pool held down by cinderblocks, and suspend the pump from the pipe, I would have been drained already. And it’s never a warm day while doing so in January and February. I gladly accept the calculated risk of the main drains leaking based on them statistically not failing. Plus, somebody pointed out the other day that they don’t have my problems of crud falling Into the pool from trees because they lived in a desert climate. My main drains suck a lot of my pollen and tree snots up so they do serve an actual purpose besides water turnover that the skimmers could handle by themselves.
 
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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
11,522
Evans, Georgia
One reason I *like* having a main drain is that if ever my water level dropped lower than my skimmer, I'd still have water flowing to the pump from that main drain. SO no burned out dry pumps.

But I can see an advantage of not having one too. That fear of line failure someday down the road....

You can always toss a hose in the pool and siphon manually, or use a sump pump.

<shrug> I guess you gotta weigh your risk/comfort level to decide.

Maddie :flower:
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,426
Bedford, TX
Looking at the other, other side... Why would you have to drain in after a rain storm? It rains here too, but my pool has an overflow port so it can't overfill.. :scratch:

Jim R.
 

Newdude

Well-known member
Jun 16, 2019
1,095
NY
My pool has no overflow. It seeps through the coping mortar cracks when it gets that high. Keep in mind if the pool is closed for 5 or more months, that’s a lot of rain and especially snow. A foot of snow is bad enough but there could be a 4 ft drift across the pool which melts right in.
 

Newdude

Well-known member
Jun 16, 2019
1,095
NY
Jim, this is my favorite part of this site how we all have our own headaches. I’m fascinated to learn what everybody else has to deal with and at some point that knowledge may even apply to myself. Even my own neighbors have different parameters than me to work with. 2 neighbors across the street have AG pools covered with a tarp. Lady down the road has an IG with a tarp. Any water they gain sits above the tarp and if it isn’t drained it just spills off into the yard. Myself and neighbor next to me have solid looplocks. They slow the water down but after a few minutes they are saturated and then the water goes through like there isn’t a cover In the first place. So we have to drain. Even if I had a spillover it would probably freeze up with an ice dam and be useless. But if I ever renovate I’ll add one just in case it works. Thanks for the tip. LOVE this place.
 

dmacpharm

New member
Jul 17, 2019
2
Austin, Tx
Thanks everyone. All great points. Leaning towards having a main drain installed but still not certain. pool will be built on top of granite with very little risk of pool settling/shifting. Probably be a last minute decision either way. Those in favor, do you think it improves water circulation (having a main drain?)
 

ping

TFP Expert
LifeTime Supporter
Jun 24, 2011
3,018
Long Beach, CA
I will say in most instances a pool having a main drain will have better circulation than a pool without one. The only disadvantage of having a main drain that I can see is if there is ever a plumbing leak in the main drain.

If there is a bit of dirt on the floor and I don't want to put the robot in, I can easily brush that dirt into the main drains. My pool does tend to collect the fine dirt near the main drains. If my pool didn't have the drains then that dirt would most likely be spread out and I might not ever notice it on the other hand.
 

IanL

Member
Aug 18, 2016
12
Lewisberry,Pa
I went with the dual main drains and it is nice being able to sweep the fine dirt into the drains. I had the pb plum it with a home run to the pad and I have a three way valve on it so I can revers the flow and make it a return for heating.
 

thetekgeek

Bronze Supporter
Jun 8, 2018
166
Nebraska
I have a main drain on my pool. I keep the valve closed most of the time (probably 90%) because the pool seems to skim better when it is closed. I run my pump at the lowest speed my SWG will let me. I will use it for winterizing, that was my main reason for having it installed.
 

SuzfromTexas

Gold Supporter
Platinum Supporter
TFP Guide
Apr 7, 2015
3,363
Houston, Texas
For my situation, a main drain is beneficial.

I live in Houston where we get torrential rains. My main drain was a blessing when the overflow could not keep up with the downpours. My average size lot drains to the street, so in flood type rains I've had water come in through the back weep holes and warp my wood laminate flooring (before I knew I could drain my pool using the main drain).

With the main drain, we were able to prevent that during hurricane Harvey,. We attached garden hoses to the pump and ran them down the driveway away from neighbors' backyards. I don't know if you can direct water from a sump pump that far away.
 

Arizonarob

Gold Supporter
Silver Supporter
TFP Guide
Mar 25, 2018
2,841
Chandler Arizona
I have 2 installed in my pool and they are plugged off. IMHO they are useless and pose a potential leak point down the road. If I was building new, install 2 skimmers both with home runs to the pad, and a suction side port for a drop in vac while on vacation. (and it’s also an additional water source for the pump should the skimmers get clogged while you’re away)
Just my 2 cents. :cheers:
 

cwstnsko

Bronze Supporter
Apr 5, 2007
65
Mesa, AZ
I think the only situations where floor drains are advantageous are some of the ones mentioned 1) Some IFCS designs are designed to work specifically with them. 2) they allow for draining down below the skimmer. 3) they can be useful if you have a pool heater to either draw in the coldest water from the bottom, or to return the hot water to the bottom.
If you aren't doing an IFCS, and you are concerned more about floor penetrations that wall penetrations, then you could always do wall drains (2 are needed, to avoid entrapment risk) well below the skimmer if you see benefit in draining down or deeper water circulation.
 

Nectarologist

Well-known member
Apr 3, 2015
530
New York
If you skip the main drain just make sure you have two skimmers that are independent of one another. This way if there is a failure in the line (highly unlikely but possible) you can still circulate water with the other skimmer. No matter the set up, I'd make sure I have two independent suction lines going back to the pump (2 skimmers or 1 skimmer & main drain). I worked for a pool company and we had a customer with 1 skimmer. The line failed and they had no choice but to fix it asap ($$) or close the pool for season and fix it before they reopened in the future. They fixed it but lost 2 weeks of swimming in the summer (we only have a 10-14 week swimming season).

I have a main drain but if I ever build another pool I would not put it in again. If you have a cleaner that will circulate the water enough for you (as will swimming in it).