Our neighbours have a dripping overflow pipe that is right up against the side of our property. I have mentioned it to them but they don't seem concerned and are not in a hurry to get it fixed. I understand that a leaking pipe can undermine foundations is the same true of a dripping overflow pipe leading to water continuously sitting against the walls. On the one hand; external walls are supposed to be exposed to water, but on the other, its continuous water

enter image description here

It's dripping such that a 6 litre watering can placed underneath (neighbours solution) fills up over night.

Obviously the issue causing the overflow to leak should be fixed but I'm trying to gauge if that's entirely my neighbours problem or if it could cause damage to my house and I should be more insistent.

If relevant we are in the UK, a somewhat cold, rainy country¹ that rarely has built in AC units

¹That makes the UK sound horrible, it's a nice place really

  • What is an over-flow pipe? Where is the water coming from ? Sep 16, 2022 at 14:07
  • 1
    the UK is a nice place, but it certainly isn't the weather that makes it so. ;^)
    – Tiger Guy
    Sep 16, 2022 at 15:20
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    I'd just knock on the door & say "Do you want me to fix that cistern overflow for you?" 30s job, assuming the level is just set a bit high. If you set it 2" lower & it still leaks, then the annoyance of the extra difficulty in making it flush twice in succession might eventually persuade them to get a new ballcock ;)) On the other hand - maybe they like frogs...
    – Tetsujin
    Sep 16, 2022 at 15:43
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    Just install a pipe that diverts the drip from there to about 3 feet to the right in your picture, further away from your property. If they don't notice or care about the drip they certainly won't notice or care about your doing this.
    – jay613
    Sep 16, 2022 at 16:01
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    6 liters in one night doesn't sound worrisome to be honest unless you have non-porous soil like clay or something. Ideally you would just divert the water further from the foundation and be done with it. I'm a little surprised it's not the white pipe that's leaking since that is much more likely to be a condensate drain.
    – MonkeyZeus
    Sep 16, 2022 at 19:12

2 Answers 2


The answer is simple yet the solution can be tricky. There should never be water constantly dripping from any source along the foundation of a structure. A simple solution is to shut off the drip. However it may be from an AC drain or some other necessary drain and cannot be shut off. Then there should be pipe added to carry the water away from the foundation. Now comes the tricky part. The pic showed your home and the neighbors home sharing a common wall. Depending on the laws in the area where you live you may , or may not be allowed to address this yourself.
If there is a manager of the complex ask them. Perhaps there is a board or some entity responsible for the common area. Tell them about this problem and be sure to include that it is more than an annoyance, but a concern with the long term safety of the structure. Since you discovered this instance there may be other areas around the building/s that have the same issue with the other owners ignorant to the long term implications. They all should be addressed. Good Luck

  • Could you take a look at this question please ?
    – Amogam
    Oct 7, 2022 at 17:32

That looks like a drain for the condensate from their air handler for their AC unit. If so, it's not something they can fix, it was installed that way. It also looks like there's a white PVC pipe exiting that wall too that might be from your AC unit.

It could also be from a leaking pressure relief valve from a water heater. Is the water warm or hot? The piping used to be done this way. If so, the neighbor should get this fixed, wasting water and energy.

You might try diverting the water with one of these water diverters, see picture below from Amazon.

enter image description here

  • 1
    Using a diverter is an excellent idea - low-cost, unobtrusive, non-controversial (hopefully) and easily installed. I'm not convinced that 1/2-1 liter an hour is a threat to the foundation, but this solution should allay any fears about it.
    – MattDMo
    Sep 16, 2022 at 17:18

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