I live in a Townhouse in NC, in a community under a HOA management. I've been doing some improvements on my patio. One of them that I couldn't find a solution is what to do with the condensed water from the AC draining. My AC is installed in the attic. 2 drain lines come from it. One is the main one which ends on my patio , the other line has an end on the soffit area of my roof (The secondary / auxiliary line coming from the dripping pan in the attic). The main line, specially in summers where I use AC a lot, creates a soggy area on my lawn, so wet that even the guys from the HOA landscape company have had hard time trying to mow there.

Since I live in a Townhouse, and no way to redirect the water beyond my property line, I've read several workarounds to solve this problem:

Some suggests to connect indirectly to sewer system like this post: Connecting condensate pump to sewer

Other suggests a mini drain well with gravel: How do I eliminate stagnant water caused by central A/C draining outside?


In my Case, I would like that mini drain well option, however, my concerning is the heavy clay soil I have. After just a few inches of topsoil, I see underneath just pure Clay. I guess that's the reason why water is ponding and creating that soggy area (see pic), specially in summers. If I create that dry well with gravel, what are the chances that the rate of water absorption of the clay underneath and around the dry well underground will be faster than the rate of water saturation of the dry well itself (being continuously and daily watered by the AC condensation line) before starting to pond water around again? I've read that a 2 Tons AC can create between 10 - 20 gallons of condensed water per day in summers. Is there a minimum size and depth for this dry well on a heavy clay soil to be effective, or is this solution not worth it on a clay soil?

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  • 1
    Do you know where the drain pipe to the sewer exits your unit?
    – JACK
    Sep 14, 2019 at 17:17
  • I have a similar issue on a commercial building with a walkway all the way around it 4 units in the attic drain to the small area between building and sidewalk. Builder forgot to put sleeves under sidewalk for drains. So my options are to let the drain run on top of the side walk or retro fit condensate pumps in attic that pump into sewer vent stack. The pump will have to sit in a basin with a drain to out side in case it fails. Or maybe put a sump pump out side in a hole that pumps the water to the sewer line leaving the building
    – Kris
    Sep 14, 2019 at 19:11

5 Answers 5


Connecting condensate and sump pumps to sewers is rarely legal these days in most places, so concentrating on a dry well approach is probably best unless you have dedicated storm sewers you can legally connect to.

One "crude but functional" test of "size of hole" is to dig it (and not fill it in, though depending on accessibility to the public you may need a temporary fence to keep children and people who should know better from falling into it) and either add water or let the condensate drip, and see how fast it goes away. The point of a dry well is to provide storage, and a larger surface area to drain away into. If you get lucky (don't count on it) you might get through the clay layer and have much better drainage - but in any case you will have a larger area to absorb water. Most dry well systems are amenable to put one in, if insufficient, add another, (connected by pipes underground) until you get sufficient percolation into the subsoil.

  • When I was in New Orleans after hurricane Katrina doing repairs all drains from a.c. units had to be connected to the drain pipe running to the sewer.. maybe it's now changed.. I won't add an answer suggesting that.
    – JACK
    Sep 14, 2019 at 18:19
  • Thanks for the suggestion Ecnerwal. Yes, percolation is the key word here. I will do the water absorption test before making any decision of the drain well. I am new owning house (just 1 year ago), and I have no idea about Clay soils. Now learning about it and how to manage it to have a good yard. This AC drain line ending there (which is the way how this townhouses were built) is making me crazy. By the way, I've read that I can't dump AC condensed water into Storm sewer, but Sanitary Sewer. Is that true? (I read that AC water sometimes brings oil and residues from AC unit itself)
    – graygoo
    Sep 14, 2019 at 21:10
  • 1
    This may well be an area where you need to consult wiht the LAHJ - "Local Authority Having Jurisdiction" which presumably is your sewer provider, whatever they might be called. If you can, or should be dumping into the sewer, that would presumably be much easier than digging up the yard.
    – Ecnerwal
    Sep 14, 2019 at 22:09

Route your condensation lines into a catch basin/barrel.

Then use the water for other purposes, water your plants, or when it is full pump it to the curb.

Distill it, drink it, save it for times of emergency. ( think, more powerful and more frequent Hurricanes on the southeast coast. )

or ?


A French Drain with a drain basin at the top (where the condensate pipe ends) might work well. It distributes the water out further so it can't pond on the surface.

  • 1
    Thanks for the suggestion. I can't extend the drain beyond the place it is doing it now (and away from the dwelling at the same time) since it's a townhouse and that lot in the back of mine is HOA's common area. Maybe if we request it to the HOA (I haven't tried it yet), and of course all neighbors must agree and willing to have an "special assessment" on their HOA fee (since ALL of them are draining their AC the same way, and even into the common area, out of their property lines, making it soggy).
    – graygoo
    Sep 14, 2019 at 21:24

Here's a different approach. I haven't tried it, but theoretically, it should work. It assumes the AC condenser unit is in the general vicinity where it would be practical to run the pipe there.

Rather than dumping the water, get rid of it in a "swamp cooler". This would be related to the kits people use to spray water mist on their condenser unit. In that case, a garden hose connects to a tube wrapped around the condenser with a series of mist heads. The condenser fan sucks the mist through. The water evaporates, cooling the air, so the condenser operates more efficiently. Those units have a problem in that the minerals in the water can build up on the condenser. The condensate you want to get rid of doesn't have any minerals in it.

The condensate won't be under any pressure, so misting heads won't work. Instead, create a three-sided screen that fits loosely around the condenser (you don't want it too close because the screen will have some air resistance, so leave a gap between it and the condenser so other air can also get pulled in. There will still be enough air movement through the screen.

You can make the frame from PVC pipe; the top would be fed by the condensate line and be sealed so the water doesn't just flow down the rest of the frame piping. Include some form of simple condensate line disconnect so the screen can be moved to service the condenser. Since it isn't under pressure, it could be just the end of the condensate line resting inside a connector to the top pipe of the frame.

Stretch something like fiberglass window screen fabric over the frame. Drill very tiny drain holes all along the top pipe, located so the water dribbles onto the screen material.

The water will flow down the screen and be evaporated by the air pulled into the condenser. The vast majority of it will be returned to the air, so you won't need to get rid of it. If you get a little water collecting under the screen, there won't be enough to create a problem.

The amount of cooling the water provides for the condenser may not be very significant. Whatever improvement you get in that regard is extra benefit. Mainly, it should solve the problem of dealing with the condensate, and the whole thing is passive.


What I did for my house was dig a hole, fill with pea gravel, route my line under the ground and had it dump into the hole and fill the hole with dirt. I didn't have to dig down very far, about 10" or so. It has been like that for about 5 years with no issues.

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