I have a main drain question on a new pool build

Dougk30

Silver Supporter
Oct 27, 2016
25
Mogadore Ohio
My pool builder is telling me that I need 3 additional main drains on for each water feature that we will be installing. So he is saying that each feature pulls the water from a main drain. I feel like I am trying to be up sold???
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,796
Bedford, TX
Doug,

A lot of large water features have their own pumps which do not go through the filter. They often have there own intake from the pool.

Tell us a little more about what type of water features, how many pumps, etc..

We have some pretty sharp pump and water dynamics people here that should be able to answer your questions.

Thanks for posting,

Jim R.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
11,061
Franklin, NC
Three is confusing to me. The The Virginia Graeme Baker Pool and Spa Safety Act (VGB) passed in 2008 required that pools not allow a drain to "entrap" a swimmer due to the suction. Shortly after passage many "compliant" drain covers were introduced which reduced the chances of entrapment, but were only allowed for existing pools, and only during a grace period for public pools.

New public pools, and by extension (because of industry practice and liability reduction) private pools are required to be VGB compliant. This required either two main drains so that if a person blocks one of them the suction can come from the second drain or a safety vacuum release system (SVRS) pump which monitors the suction pressure and turns the pump off if it senses a blockage.

Again, I don't understand 3.....
 

mas985

TFP Expert
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May 3, 2007
13,823
Pleasanton, CA
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Again, I don't understand 3.....
I think it is one set for each water feature which probably has it's own pump. Sharing MDs is not always possible given the flow rate when all the pumps are on.

Doug, I would recommend having separate intakes for each of the water features that has it's own pump. However, they don't necessarily need to be floor MDs. They could also be wall ports.
 

Dougk30

Silver Supporter
Oct 27, 2016
25
Mogadore Ohio
Thanks for the input. Its good to know that it will help.
There were 2 main drains in the floor already figured into to the project then they added three more for the three water feature that we are doing. The additional 3 will be put into a bench that we are putting in it. The additional 3 were added as a change notice and he wanted to charge me an additional $900 per drain. It felt kinda shady.
 

mas985

TFP Expert
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May 3, 2007
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Pleasanton, CA
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Where are they located in the bench? Close to body parts?

Is each drain connected to their own pump?

Is there a single cover for each or are they dual drains like the MD?
 

grottoguy

LifeTime Supporter
Aug 24, 2014
462
NJ
I have two sets of main drains in the bottom of my pool. One is associated with my variable speed pump and the other with my pump for my grotto. I also have a set of main drains on a wall (3 drains (instead of 2) actually to minimize the risk of entrapment) that runs my waterfall pump. One thing I didn't follow in your question was whether he was charging you more after it was already agree that you were getting extra pumps. If so, it seems like whatever he charged you should have already taken the extra main drains into account as he should have known those were needed.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,823
Pleasanton, CA
Pool Size
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But still have a split suction line with drain covers, correct?
It depends on local code but that would be the safest.

I think an easier solution would be to use another pair of MDs in the same location that are teed together with 3" pipe (or maybe larger depending on total flow) and then split again to each pump. That way you have the split MD without having to have 6 total. But to meet VGBA codes, the water velocity needs to be kept below 5'/sec so that may require larger pipe but just for the MD tee and pump manifold. It might require larger covers too.
 

bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,529
San Clemente, CA
That's an interesting idea to build a pump suction manifold and have the pumps share suction lines.

I've seen 2-3 lines share a single drain cover (that are then teed to another cover) quite often. That works well so long as the covers are rated for the flow.

Nothing looks worse than a pool littered with drain covers. I just saw one with 18 this morning.
 

JamesW

TFP Expert
Mar 2, 2011
21,516
If you have a variable speed main pump and valves, you should not need a separate pump for each water feature. Just adjust the vsp and valves to get the flow you want to each feature.

If you do go separate pumps, get the right pumps. Too often the builder puts a high head pump like a WhisperFlo, on a feature.

Features usually need low head pumps and manufacturers make water feature pumps specifically for water features. They are much quieter and use much less power.

Alternatively, you could use a single IntelliFlo XF and valves for all of the features. By adjusting the speed and valves, you should be able to get the effects you want.

Can you describe the features requirements like flow and pressure?