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California Drainage Law

Updated on February 24, 2023

  • can a neighbor drain water onto your property
  • can i sue my neighbor for water runoff
  • how do i deal with my neighbors water runoff

The weather forecasters claim California is in for a strong El Nino this year. And, although with this drought our state could definitely use some extra rain, if you live on (or below) a hill, the prospect of a lot rain may have you nervous about water damage to your property – especially if your uphill neighbor has made changes to his or her yard that may increase run off into yours. Here are some water law facts to help you hillside homeowners assess surface water run-off issues.

Uphill Property Owners Liable for Damage

So in California, uphill property owners might be liable for property damage to their downhill neighbors caused by surface water run-off if they failed to exercise reasonable care in the use of their property so as to avoid injury to the adjacent property through the flow of surface waters. (Contra Costa County. v. Pinole Point Properties, LLC (2015) 235 Cal. App. 4th 914, 926.) However, it is equally the duty of any person threatened with injury to his or her property by the flow of surface waters to take reasonable precautions to avoid or reduce any actual or potential injury. (Id.) In short, neighbors need to behave reasonably towards each other when it comes to surface water run-off.

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Water run-off onto your Downhill Neighbor’s Property

Imagine that you are the uphill property owner and you come to learn that you need to construct a retaining wall. However, doing so may increase surface water run-off onto your downhill neighbor’s property. There is a drainage ditch on your downhill neighbor’s property that is in bad repair, but if it is fixed, it could easily handle the extra water flow.

In such a situation the uphill property owner is unlikely to be found liable for building such a retaining wall (particularly if the same is necessary to protect his/her property), even if the increase water flow damages the downhill neighbor’s property. This is because if the downhill neighbor refuses to fix and maintain the drainage ditch – i.e. refuses to take the action that could have prevented the damage – that downhill neighbor is acting unreasonably in the face of the uphill neighbor’s reasonable improvements.

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Bottom line, when it comes to water run-off issues, if all the neighbors involved act reasonably with respect to their own property – and hopefully with consideration towards each other’s – questions pertaining to liability and damage can often be avoided.

If you have questions regarding damage to your property caused by surface water run-off (or any other real property legal questions), please feel free to contact our best real estate attorney at Schorr Law to inquire about a free consultation.