I have a 20K gallon pool that I need to drain. I don't have a proper sewer cleanout, but I do have access to a waste line that is on the exterior wall of my house, adjacent to one of the bathrooms. It has a two inch cap.

Is it safe to drain our pool into this waste line? Note - I cannot drain into the street or yard.


Please let me clarify when I ask if it’s safe - will running 20k water through the 2 inch waste line cause any structural problems? I understand this to be different than a 4 inch clean out line. Also, the city allows us to drain into the sewer/waste line but not storm drain (street).

  • 1
    Depending on where you live most municipalities would not be happy with you pumping your pool into the sanitary sewer. Unless you live in a place like Vegas than it's required. There isn't a storm drain you can pump it into?
    – JD74
    Commented Jun 12, 2023 at 2:49
  • 10
    This is s matter of local regulations. Ask your town
    – keshlam
    Commented Jun 12, 2023 at 2:53
  • 3
    If the question is 2" vs 4, it depends on the pump rate not the pool size. What do you mean bystructural?
    – jay613
    Commented Jun 12, 2023 at 9:19
  • 3
    Depends on the local system, and the OP has stated that their local system wants it in the sanitary sewer, not in the storm sewer. Can also depend on the weather, depending on the local system. Those that are prone to excess infiltration (or are combined storm/sanitary) may not have excess capacity when it's raining.
    – Ecnerwal
    Commented Jun 12, 2023 at 18:41
  • 2
    Get a second pool and put the water there. Commented Jun 13, 2023 at 14:59

3 Answers 3


The pipe won't wear out from 20,000 gallons of water, or 2,000,000 gallons, if that's what you're asking. It may take as much as 3 weeks to pump out, though, since you can't exceed the gravity flow rate in the 2" sewer pipe, or you'll have pool water spouting up into your bathroom fixtures.

You might be able to have a pool company water truck come pump the water out for use elsewhere - if it's not in a horrible state. Depending on several local factors you might even get money for that. And it won't take weeks.


If you are concerned about the flow rate:

Siphon it out with a thinner hose. Stick the exit of the hose loosely into the waste line. The thinner hose will prevent an flow rate too high for your waste line. Since the connection is loose, it will prevent an eventual pressure buildup.

  • 3
    The drain access point would have to be lower than the bottom of the pool for siphoning to work.
    – Ecnerwal
    Commented Jun 12, 2023 at 18:38
  • 4
    @Ecnerwal No the end of the hose you use would have to be lower than the bottom of the pool. Where it enters the waist line is irrelevant.
    – Kevin
    Commented Jun 13, 2023 at 6:36
  • Then the clog you get from having a hose jammed way down your sewer line will become the problem. And you'll have a severely contaminated hose when you pull it back out of there. Or you may have the end of the hose jam on a fitting and not want to come back out of there. Fun times.
    – Ecnerwal
    Commented Jun 13, 2023 at 13:30
  • Or, just have a few inches of air gap. However, the statement in another answer about the amount of time that would take to drain would be even longer ...
    – Steve
    Commented Jun 13, 2023 at 21:27

As mentioned, siphoning works. This is the simplest and it works, we have done it dozens of time. And it wont take weeks. Its cheap to sacrifice the end of the hose which you can chop off.

Siphoning will work, as long as tbe hose exit is lower than the bottom of the pool. Even if it isnt, you gould empty some of it.

For larger pools, we have used several hoses and even a drill pump like this. It attaches to your drill and is cheap to buy.

enter image description here

Or you could rent a small submersible pump.

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