Stormwater runoff from neighbouring property

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johno1234

2838 posts

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#320162 12-Jul-2025 09:40

Storm water running off our neighbour's property onto ours. Their house design looks dodgy with no eaves. The gutters always overflow in heavy rain with sheets of water running down the sides of the house and windows. That place is likely to be rotting away internally.

But some of the water not being captured is visibly flowing across the boundary through or under a stone and concrete retaining wall before going into a stormwater drain on our property.

What could or should we do?

They are Chinese and I am sure from previous hellos that there will be a language issue.

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2408 posts

Uber Geek

#3393495 12-Jul-2025 11:59

its not their problem, as long as they don't divert water onto your property. water falling onto the ground and running downhill onto yours is "natural runoff" and is your problem to deal with.

the only time its their problem is if they divert water flow onto your property. most common example is putting a drain in and diverting the water sideways to the neighbor on the side instead of the neighbor below.

Rickles

2938 posts

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#3393500 12-Jul-2025 12:08

Suggestion: Get a Chinese speaking friend to draft a very polite and nice letter telling them that the blocked gutters will be damaging their house, particularly given NZ's weather .... or translation services or CAB could be helpful with this.

Presumably they own the house so should be interested in advice .... or if rented maybe ascertain the owner or property manager.

Could be a pleasant first step to remedy some of the problem?

johno1234

2838 posts

Uber Geek

#3393531 12-Jul-2025 15:28

Rickles:

Suggestion: Get a Chinese speaking friend to draft a very polite and nice letter telling them that the blocked gutters will be damaging their house, particularly given NZ's weather .... or translation services or CAB could be helpful with this.

Presumably they own the house so should be interested in advice .... or if rented maybe ascertain the owner or property manager.

Could be a pleasant first step to remedy some of the problem?

A Chinese friend tells me that Chinese people habitually avoid spending money on building maintenance as they don't see it as good use of money. I can't fathom that when it sees the asset depreciate faster.

Ragnor

8224 posts

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#3393996 14-Jul-2025 23:53

What region?

In Auckland I contacted my local ward councilor, who was actively engaged in following up storm water issues after the flooding events in 2023.

I received a decent reply from storm water planners in the council, including copies of the drainage plans for uphill neighbors from council property files.

They also stated quite clearly:

"Downpipes have to be connected to a stormwater system and are not allowed to discharge onto the ground surface so we can pass on this information to council’s building compliance team for inspection/action. It would help if you could take some photos to confirm which properties to send the inspectors to."

mattwnz

20186 posts

Uber Geek

#3393997 14-Jul-2025 23:57

My area doesn't have a storm water system for houses, so downpipes must go into a soak pit. But that seems to only be policed on new builds.

Bung

6510 posts

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#3394002 15-Jul-2025 00:27

johno1234:

But some of the water not being captured is visibly flowing across the boundary through or under a stone and concrete retaining wall before going into a stormwater drain on our property.

Just for argument's sake, if it is going into your drain is it creating a further issue?

eracode

Smpl Mnmlst
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#3394060 15-Jul-2025 08:27

Ragnor:

What region?

In Auckland I contacted my local ward councilor, who was actively engaged in following up storm water issues after the flooding events in 2023.

I received a decent reply from storm water planners in the council, including copies of the drainage plans for uphill neighbors from council property files.

They also stated quite clearly:

"Downpipes have to be connected to a stormwater system and are not allowed to discharge onto the ground surface so we can pass on this information to council’s building compliance team for inspection/action. It would help if you could take some photos to confirm which properties to send the inspectors to."

This is correct. Some years ago good friends of ours had exactly this problem and it was causing flooding in their basement. The uphill house next door had blocked downpipes and drains that prevented the water taking its planned course - which was to discharge through underground pipes into the gutter on the street.

They contacted Auckland Council who were very helpful and contacted the owner and compelled them to fix things - threatening action if not done.

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johno1234

2838 posts

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#3394383 15-Jul-2025 17:05

Bung:

johno1234:

But some of the water not being captured is visibly flowing across the boundary through or under a stone and concrete retaining wall before going into a stormwater drain on our property.

Just for argument's sake, if it is going into your drain is it creating a further issue?

It might do... so far it is coping. It may be undermining the retaining wall but you can't tell.

duckDecoy

900 posts

Ultimate Geek

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#3394389 15-Jul-2025 18:04

If you think it might cause you problems if down the track the retaining wall fails then you should definitely get the council to compel them to sort their gutters. Otherwise this might become am expensive you problem.

Bung

6510 posts

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#3394390 15-Jul-2025 18:10

I was thinking more in terms of a local soak pit being overloaded vs discharge into council stormwater. If the retaining wall was properly designed and built it should be ok.

tweake

2408 posts

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#3394402 15-Jul-2025 19:22

think about this for a sec,

what would it be like if the house wasn't there. all the rain would hit the ground, none would go down a storm system and all of it would run off to properties below. that can be quite a bit if your near the bottom of the hill with no houses above.

elpenguino

3431 posts

Uber Geek

#3394408 15-Jul-2025 20:27

eracode:

Some years ago good friends of ours had exactly this problem and it was causing flooding in their basement. The uphill house next door had blocked downpipes and drains that prevented the water taking its planned course - which was to discharge through underground pipes into the gutter on the street.

I don't like the idea of relying on someone else to do maintenance on their property to prevent something like that happening to mine.

I'm in a similar situation to OP - my back lawn is a bog most of winter. I don't know how much runoff it gets from the uphill house but I plan to take matters into my own hand and drain the yard. Sometime.

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johno1234

2838 posts

Uber Geek

#3394411 15-Jul-2025 20:52

tweake:

think about this for a sec,

what would it be like if the house wasn't there. all the rain would hit the ground, none would go down a storm system and all of it would run off to properties below. that can be quite a bit if your near the bottom of the hill with no houses above.

That’s different and this is why councils care about non permeable site cover.
If the site is undeveloped water is absorbed over the whole area into the ground. Where there is non permeable site cover water is concentrated into small areas, cannot be absorbed and runs off elsewhere or floods.

Bung

6510 posts

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#3394469 15-Jul-2025 21:53

Usually it takes some time for the ground to start absorbing water. A quick downpour tends to just run downhill.

cddt

1576 posts

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#3394512 16-Jul-2025 09:12

Ragnor:

"Downpipes have to be connected to a stormwater system and are not allowed to discharge onto the ground surface"

I assume this is not retrospective. Our old house definitely had one downpipe discharging onto the ground... built 1930 though.

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