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FAQ - Swimming Pool Main Drains
77Suction Entrapment Free Swimming - 100% Safety
What is swimming pool suction entrapment?
There are five forms of suction entrapment. They're easy, yet essential to understand to "get" this whole issue.
1. Body entrapment (a section of the torso becomes entrapped).
2. Limb entrapment (an arm or leg is pulled into an open drain pipe).
3. Hair entrapment or entanglement (hair is pulled in and wrapped around the grate of the drain cover).
4. Mechanical (jewelry or part of the bather's clothing gets caught in the drain or the grate).
5. Evisceration (the victim's buttocks come into contact with the pool suction outlet and he or she is disemboweled.)
How can I drain my pool without a drain?
The funny thing is, drains are hardly ever used to drain a pool! How goofed up is that?! TWO big points to remember:
1. With a composite fiberglass pool, there is no need to empty your pool for general maintenance as you would with a concrete pool. But if you ever did want to drain your pool to add say, a pretty tile mermaid mosaic like we did in our pool, all you have to do is use a sump pump or open your filter plug. That's what a pool professional would do. A sump pump is the quickest, most efficient way to drain a pool. So no, you don't need a drain to drain your pool. The "drain" in your pool is not like the drain in your bathtub!
2. Remember---NEVER drain your pool yourself. Always consult with a pool professional. Issues involving hydrostatic pressure could really mess up your pool and deck area.
So what is a drain in a pool if it's not like the drain in my bathtub?
A pool "drain" is actually a misnomer. A pool doesn't drain anything. That drain is really a suction outlet. It's sucking water out of the pool and taking it back to the filtration system, then back again to the pool. It's like a straw. And the pump is like you. Entrapment is like when you're sucking up that strawberry shake from Dairy Queen and nothing comes up---then you quickly discover a strawberry "entrapped" at the end. Stop sucking and the strawberry releases. Your pool requires a powerful pump to "pull" that liquid back to the pump. So why in the world would you want that "outlet" for suction inside your pool where those sweet babies of yours are swimming?
Then how do you get water to the pump without a "suction outlet?"
Good question! The water comes by way of a wonderfully, brilliant little device known as a skimmer. A skimmer is a gravity-fed product that simply collects water from the pool via gravity and simultaneously skims out leaves and gunk. It then deposits the water into a pipe that is connected to the pump. The pipe is completely unreachable by swimmers. No one ever sees the pipe that goes to the pump, which is housed deep inside the skimmer, below the crud collection basket. So there you have it. Easy breazy water collection without a bit of danger.
I had another builder tell me that if we didn't have a drain system, our pool would not circulate properly.
This is another one of the biggest objections by pool builders for not having "bottom suction" in a pool. The scary thing is, it is the least understood. It is based on the "belief" that water becomes stagnant in the deeper areas. It is not based on science. For some awesome science on this whole concept, the must read here is the Fluent / Trilogy Pools study on pool circulation. This study clearly shows that drains not only are unnecessary, but they do not improve the circulation in a pool or enable its ability to clear contamination. Imagine that! You don't need to be a rocket scientist to know that there is no reason to have a drain.
Aren't dual drains safe?
Yes. For the most part. BUT, the real question is, would you rather have your loved ones swimming in a pool that is safe "for the most part" or in a pool that is 100 percent safe? Here's the deal. Systems fail. That is why Florida requires "layers of protection." In the event that the second drain fails, a vent line or a suction vacuum releif system will release the suction and release anyone stuck on the drain. That's just great until the vent line gets clogged with yard clippings or rodent, or the svrs runs it's life expectancy. (Have you ever heard of an appliance that doesn't eventually fail?) Plus then there is the issue of the drain covers. Guess what happens to plastic in a chlorinated environment. You guessed it. Corrosion. The screws become loose eventually and the plastic gets all funky. Now you have drain(s) that have loosey-goosey covers that were supposed to be protecting you from the last 3 forms of entrapment. Yikes, and to think you didn't even need those drains in the first place. See how frustrating this is?
A spa and a pool builder told me I had to have a drain in my spa in order for it to run properly. Can you build a spa without a drain?
Absolutely! In fact the spa is the most dangerous place for a drain. Because a spa is typically only 4 feet deep, where do you think all the kids like to congregate? It's the most fun for kids to goof around in a little warm body of water, and guess what they do? Yep, they investigate the drain(s). They're easier to get to in a spa that's for sure!
We (www.mymermaidpool.com) are a custom swimming pool contractor/builder in the Orlando, Florida area have built many, many pool/spa combinations with no main drains. The reason a pool builder would want to use a drain is because they need to supply the pump with water and a bottom suction seems to be a great place to get it. The thought of using skimmers on a spa is foreign. We use multiple small skimmers and supply our pump the same way we do our pools---through a gravity fed system. Our spas circulate beautifully and have zero hazard.
You can have a 100% entrapment free pool. Expect your builder to understand this concept. If he/she does not or tells you otherwise, please contact someone who can assist you. Contact me at Maria@mymermaidpool.com if you need further help. We are a custom pool builder/contractor and we mostly work in the Central Florida/Metro Orlando, Florida area -- Orange County, Lake County and other areas but we also work with DIY pool projects throughout the country so we know what we are talking about. There should be no more suction entrapment deaths. Together we can stop suction entrapment.
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Thanks for the nice comment. I'm glad it helped. If it were my pool, I would either plasater over the drain, or convert it to a return. I wouldn't mess with an approved cover, because regardless of how "approved" they are, they still can become loose and/or corroded and will require ongoing maintenance. In addition, the "approved" covers don't protect against all forms of entrapment. One major being mechanical entanglement. (Jewelry, hair, swim suit, etc caught on cover.)
In most cases, for a basic residential pool, that drain can be eliminated, which is the easiest way to go. There are a few more details associated with it that I will be addressing in a new hub page. In the meantime, switch off your drain (you should have a valve that turns off the drain) and confirm that the pump gets enough water to operate. It more than likely will. That confirms you didn't need the drain in the first place.
Stay tuned for more...
With no bottom drain in an inground pool, what happens with hydrostatic pressure?
Hi Karen,
I'm sorry I missed this comment a couple months ago!
A drain is not necessary for hydrostatic relief. A hydrostatic relief valve can be installed at the bottom of the pool. Basically, it's like a bathtub plug that is spring loaded. If the hydrostatic pressure is greater than the pool water it will open thus equalizing pressure.
Hope that helps!
ok your website is wonderfull.
I feel more safe about the main drains and how you shouldn't have them,but I am wondering about the pools with main drains and drains on the side of the pool...does it make a pool a little bit safer with the side drains?
Hi Tom,
Thanks for your kind comments. As far as drains on existing pools, that's a whole 'nother blog! For general safety tips for swimming in pools with drains, check out http://hubpages.com/hub/Beware-of-Pool-Drains
Side drains...meaning drains built into the wall of the pool: If there's suction in the pool, a person is still in danger. Same issues apply. Entrapment and entaglement are still a possibility and I would echo the cautionary words as applied to floor drains.
The question should really be, is the drain necessary in the first place? A simple turnover and velocity calcuation can answer that. We've built hundreds of residential pools, with all sorts water features and different plumbing requirements and not one has "needed" a drain. That includes spas.
As builders, we have believed there is little, if any value, to building a pool with a drain, considering the horrific risks involved. To knowingly put a risk like that in a pool is like deciding to drive without a seat belt.
I hope that answered your question...my coffee is kickin' in! :)
Why don't you just turn the pool pump off when people are swimming in the pool. That way you don't have to worry about entrapment.
Or instead of plastering over the drain hole which means you have to drain the pool which can create another potential problem, close the main drain valve. The pump will suck only out of the skimmer. You can also take the handle off so no one turns the main back on. If you don't have a valve, get one installed.
My pool is 20 by 40 with two skimmers and a main drain.
I have a leak in the main drain can I plug it with a rubber plug and just have circulation through the skimmers without issues to the pumps or pool safety?
thanks scott
Scott,
The answer is mostly about gallons per minute and velocity. You probably have a valve near the pump where you can turn it so that you only pull from the skimmers. The presumption is that this set up is adequate to move the gallons and not have a high velocity in the piping. My guess is that the piping from the skimmers will be adequate to do the job.
The key is to understand the hydraulics. The skimmers probably are capable of moving 60 gpm each. The piping to each skimmer is probably set to move that amount also. The pump is probably not capable of 120 gpm -- the exact rating of the pump is a function of the pump rating and the size and distance of the piping from the pool to the pump. My guess is that the pump is a 1 hp which is probably in the 60 gpm range with all the restriction in the piping. So. if you have a 20x40 pool with an average depth of, say, 5 feet, you will have 4,000 cubic feet of water or about 30,000 gallons. That is a lot of water to move. At something like 60 gpm it will take 500 minutes or less than 8 hours to move 100% of the volume of water. Usually, the turnover of 100% of the water in 8 hours is the requirement of code. So...........yes, it probably would work.
Don't let any pool guy bone-head tell you about circulation and the need for a drain. Circulation is more about the return fittings and mixing -- lots of studies by thoughtful people in the industry back this up. You should be fine.
The plug at the pool and isolation of the valve at the pump area will make things OK as to the leak.
Pool safety is enhanced without a drain. Make sure that there are no opportunities for entanglement when you plug the drain so no one gets stuck on it.
The pump is at a slight risk -- if the water level goes below the skimmers you could burn up the pump. You can add an autofill device if you were really concerned or just keep the water level up. We've never had a problem in 8 years so I wouldn't worry about it. We don't have an autofill device. If our water level lowers, we just throw in the hose.
I hope that helps. Let me know if you have questions. I am off to my pool to take a swim right now!
Smiles!
Maria
I agree that a system that is 100% safe for anyone swimming in the pool is the most important thing to look for. The last thing anyone would want is the knowledge that their swimming pool caused someone to drown.
Parents need to teach their kids that the drain is dangerous, even if it is not on. Kids have got their hair and fingers stuck in them before. They are just not safe.
I am remodeling my pool in California, as I agree that there is no need for a main drain (I plan on filling it and covering when we plaster) my question is, do you know if they are required in California, thanks. Ron
I have worked in the industry for 15 years and have seen many pools without functioning main drains. The pools work fine. Main drains are a remnant of early pool builders, not knowing much about hydraulics and circulation, who added these to keep water from stagnating in the deep end. They were never really needed. Especially in current day pools with automatic cleaners, the cleaner acts as a roving return line greatly increasing the overall circulation of the water throughout the pool.
I will say however that I prefer to have main drains (anti-entanglement, anti-entrapment) in the spa for maintenance purposes. With the spa suction on, sand, dirt and small debris can be swept into them easily for a quick cleanup without having to pull out the vacuum hose. Properly installed and maintained the risks of an incident are quite low, as with the 120v lighting in the pool. (Check your GFCI periodically)
Ron--Happy to see you're planning to bury your drain. Technically, drains are required in California, unfortunately. Crazy.
Bill--Great comment. If anything, however, drains in spas are the most dangerous because of the relative ease in access by kids and adults alike. A spa is shallow. Kids LOVE to explore anything in a pool and they can easily get to a spa drain. Personally, I would never put a drain in a spa. As a builder, we never did. Keeping a spa debris-free is nothin'-but-a-thing and certainly for the few specs that accumulate, nothing I would risk with a drain.
As you said, if properly installed and maintained, the risks are low....my problem with that is in all reality, these drains are more than likely NOT to be properly maintained. The "busyness" of life gets in the way of even the most vigilantly-minded homeowner.
I love your thoughts concerning the obsolescence of drains. Brilliant.
Jon---sorry I missed your comment! Great idea on closing off the main drain valve and taking the handle off for an existing pool. And its easy fix. I wouldn't, however, just turn the pump off when swimming; after all who wants to swim in stagnant body oils. Ewie! And that's not even mentioning what the kids are doing in the pool.... :)
Maria, what do you think about over chlorinated hotel and public pools? How bad for your skin are they?
That's funny you say that Maria. I just read an article about how unsanitary public pools are!
Again - Useful information. In fact I am planning to have one in my back yard and this hub will help a lot to get a preliminary idea. Thanks for getting such a wonderful thought and writing this hub.
Thank you! Best wishes to you! Love your pool!
Hi,
this information is really interesting. I have a question for you if you don't mind. My wife and I recently removed the dirt from the cement pool that was filled in when we moved into our home. The drain is still intact and usable but id like to cover it up. If the pool is 12'x 30' and six feet at the deep end, where should we put the skimmers if we don't have a drain? We were thinking of a return on the deep end shooting toward the shallow end and a return on the opposite side wall closer to the shallow end. Is this enough without a drain?
Thanks
Thanks Bruce. Ultimately it's a standard calculation to determine the requirement turnover and supply of the pump. In our experience, one skimmer would provide ample supply for the pump with a pool the size of yours, with 2 returns and a water feature. Ask your pool professional to calculate the turnover in regards to the pump, or you can do it yourself with the manufacturer's specs. Distance of plumbing runs along with size of piping, number of turns all play into that calculation.
Placement of the returns in places you mentioned make sense. It has been our experience that water flow in a random motion actually is just as effective as a circular motion. The goal is to encourage movement.
Hope that helps!
I am refurbishing a pool (18 x 36 lazy L) at a house that I just purchased and it has one return in the center of the deep end and no drains other than the skimmer. I was considering adding a return in the shallow end to improve surface circulation and enhance the skimming. As this would involve breaking/patching concrete, I would like to know if you think this is advisable? Thanks!
Benny
Thanks for the note. Circulation is really a function of the 'push' side of the equation. As long as you are pushing the water into the pool and creating movement the location of the skimmer is not so much important. Skimmers provide the gallonage for the 'push' so as long as you are getting enough water, you really don't need another skimmer. You need to see about the size of the pipes (not too small for the pump) and the run time of the system. Remember too that in pumps at least bigger is not better so don't just throw a big pump on the system and think that is helping. The power company will love you but it will not help.
Moving 100%+ of the volume of water each day is usually all that is needed so figure the flow rate (like 50 gallons per minute) and figure out how many gallons in your pool -- 18x36x5 ft average depth is X cubic feet. Eight cubic feet to a gallon and you have it. This would be about 26,000 gallons and would need 8-9 hours of run time a day.
You might want to add a return or two to the pool. Use your imagination. Add a waterpot falling into the pool to make the construction easier. OR Add some jets that shoot from the edge of the decking to pool so you don't have to cut the deck.
Have fun!
I am building my own pool. Where can I get more info like this and maybe a little more detailed
Thanks
Rand@bananabeachbums.com
I have a pol 2yrs old. I am confused about how much to open the skimmer valve, the main drain and the pool cleaner valve. When do you close and/or open the main drian valve?
Thanks
Brenda,
Here is what you could do.
First, the vacuum cleaner line I assume is a suction line. It is probably about 12 inches below the water line -- just low enough to entangle hair and drown someone if the situation was there. The valve should turn off the vacuum line whenever it is not in use (I'd never use it). More importantly that fitting should be an approved spring loaded cover that snaps shut when the hose is not in it.
The drain and the skimmer both have the job of getting water to the pump. The skimmer is what I would have on 100% and the drain on 0%. With this you would minimize the suction risk of drowning on the drain. You still can get clothing stuck on the drain or a toe or jewelry but you would not it least have the suction. The 100% skimmer use would maximize the water off the top of the pool, where, most of the body oils, sun tan lotion, pollen, etc are in the pool. You can also get an adaptor for the skimmer so that the vac line can go into it, too.
As for circulation, remember that where the water comes out of the pool is of little importance. To circulate the water, point the return fitting down and create movement. Don't go for any clockwise or counterclockwise rotation. That just sets you up for circulating the top foot of water, only. Just get the water pushed in a bunch of directions.
Overall, you can have a safer pool by doing the skimmer only. You can also have the drain covered up (think about that for now or at least when you resurface or otherwise work on your pool.
Remember that suction and other entrapment is not the only safety concern. Make sure you have a barrier in place, that you always supervise children, never dive head first and many other things. Check out the web for other safety tips.
Pools are fun and relaxing. Enjoy it!
Where can I find a plug to plug the bottom drain permenently
Talk to your pool professional. Depending on the type of pool you have, they will be able to seal that opening. (Sorry for the delay in response!)
Hey,Genius! What happens when your skimmer baskets are plugged up with seeds and leaves from trees and flower petals? Your pool just won't circulate as well? No, your pump will cavitate and if left unattended, probably burn out. The same could be said for water level below the optimum height for skimmer draw.
If your main point is that pool safety is of primary importance, I certainly agree!
The industry standard is to address potential hazards, not scrap 50 years of circulation improvements.
Further, you're throwing around alot of misinformation, which has no doubt been hyped up recently.
36 people lost to suction entrapment in 31 years is 36 people too many. how many of those people were killed by wall suction fittings vs.a main drain? -The vast majority?How many since anti- vortex covers came out in the 1980s? How many since dual main drains "t-eed" to a singler line? How many since the requirement of supplimental vacuum release? NONE.
How many people have drowned in swimming pools since 1980? THOUSANDS!
Diving accidents? Hundreds.
Let's all get really safe and stop building swimming pools!
Short of that, here's a better idea: let's continue to improve our industry by promoting safer pool usage (no unattended swimming, no improper diving, no intoxicated pool usage, no access by small children, etc.), AND promote better pool installation and service techniques and equipment that anticipate and eliminate hazards. This is an on-going process, people will always find new ways to get hurt.
hi , I just bought a house with a 48x24 ft inground pool that has a vinal liner . pool man says the deep end suction outlet is leaking and wants to plug it, says I dont need it. Ive never owned a pool before, what do you think? there are 2 skimmers in the deep end and 2 retuns in the shallow and 1 return in the middle . Thank You John
Entertaining hub!Well-written article.
I would like to know how to install a Hydrostatic valve in my main drain. It is vynal lined and the liner is only 1 year old. I am having trouble with water behind the liner, even after having a $6000 retaining wall built this spring!
Thanks in advance
To be honest..IT's to massive for the pool.It could have been a little lower and maybe wrapped around the corners so it would seem more real instead of a big mass of rock at the edge of the pool....sorry just my opinion. Dave....
Dave,
The rock was something that was in the homeowners garage that we were to add to the poolscape. The photo shown was taken at completion of the project. After the foliage grew in the rock was then in proper proportion. The pool is a hidden oasis and really a great tropical retreat in the middle of suburbia. Thanks for your comments. Maria
I agree with this article, main drains are quite unnecessary. I live on a street that has two houses with inground pools with vinyl liners and neither of them were built with main drains and both pools were built 20+ years ago by different contractors. Neither homeowner has ever had a problem with circulation in the deep end or the water becoming stagnant. Perhaps the exception to this is public pools which are much larger than residential pools and may benefit from main drains along the bottom/sides as long as the covers are up to code which sadly we all know most are not even with the strict laws regarding them.
I hired a pool contractor to replaster and repipe my pool in California. He is eliminating the main bottom drain and installing two suction inlets on the wall which are about 18 inches apart. I have been looking around for information just to make sure that this is legal but cannot find anything on this subject. Your thoughts on this will be appreciated. Thanks
JR
The suction outlets may be approved -- that is legal -- but they still pose a hazard as someone could tangle hair, jewelry, etc or WHEN the grate eventually fails an arm or finger could get stuck -- all underway -- all with the potential of drowning. So, ask your contractor to calculate the hydraulics. I seriously doubt that the pool needs to have more outlets. The skimmer is probably all that is needed. The better option is probably to make those suction outlets an inlet (return fitting) for your pool. Circulation is about push, not pull of liquid.
Ask your government inspector or contractor to show you, in the code, where it says that it is required. Read it carefully. Demand them to show you why you have to have them.
Best of luck to you and happy swimming. Maria
I just purchased a house with a 38 x 16 vinyl lined pool. The current liner is shot. Very little water in the pool. According to the professional it has been winterized properly, but I don't trust the bottom drain. I want to seal it before I install a new liner. Can you tell me what would be the best material to use to fill in the main drain, and if there is anything special I need to do.
thanks in advance.
Wow that pool in the photo has aires rock at one end. impressive.
Regarding complete inground pool draining,and pulling the hydrostatic plug or drilling a relief hole in order to prevent the pool from popping because it will remain empty. Is the function of plug the plug or drilling a function of a pool cleaning service or does this fall under the duty of a pool contractor- where can i find the legal definition/florida building code that would spell this out as to what the ruling on this is, either defined as a function of pool service or pool contractor- please provide sources of proof if you can find it thanks much
Ok so I maybe just 12 but the pool drains and filters scare the poop out of my really when ever I get near one I have to get away asap or I will flip the just look soo scary when I was 8 I took swimming lessons and one of the instrusters took me and forced me in the pool I was soo scared I still when he grabed me and but me on the ducky and made me go down I was soo freaked but one time every one had to move around the wall and a different instructor was helping us and I was at the filter part and I told him I was scared of that part soo he let me swim by and the bad part both of that happend on the same day the drains and filters and lights on or off and jets scare the poop outta me soo when I go swimming it is soo hard I always have to find the drains filters lights and jets and sometimes the thing that fills the pool the Faust I think that's how you spell it
Thank you so much for your fantastic wedsite.
I am in the beginning of installing a Fiberglas pool 21x11 and 4.1/2 feet deep in my yard, and I was very confused about installing a main drain.
I am now clear on not having one, and planning on having one skimmer, would that be enough?
Thank you again
Hi
We have an existing pool (about 6 months old); but need to add a inlet. In is a concrete fiberglass pool.
How do we go about doing this?
Please help
Hi I was just wondering how I can set the valve to keep the main drain off. Right now I have both skimmers running, and currently the valve is facing up toward the filter and it makes sort of an upside down T ( _I_ ). If I turn the valve to the right or left so that it facing toward one of the pipes, will this close down one side or the other?? or will it cause the main drain to be turned on????
Susan Ogle 3 years ago
This is a great web page with understandable explanations; thanks! We have a residential pool that has a skimmer and a main drain. In light of the explanations regarding skimmers providing the suction much below the crud basket, is there any suction associated with the existing main drain that would cause danger? Could it be plastered over and/or should the drain be replaced with the new CPSC approved drain cover?