The Regulation
City of Raleigh’s residential stormwater regulations are primarily related to impervious surfaces and apply to residential lots based on size and two categories: Lots recorded/created prior to May 2001 and lots created after May 2001.
1. Grandfathered Lots
If your residential lot was created prior to May 2001, which can be determined by checking the recorded plat with Wake County (or a quick check may be the year your home was built if it is the original structure), you are considered a “grandfathered lot” (UDO 9.2.2.A.1) and are subject to maximum impervious limits based on your lot size.
- For residential lots 1ac or less, maximum impervious limits are determined by your residential zoning:
- R-1 = 20%
- R-2 = 25%
- R-4 = 38%
- R-6 = 51%
- R-10 and all other zoning districts = 65%
- NOTE: If all existing impervious surfaces were placed prior to Nov. 27, 2016, you may be eligible for an additional 400sf of impervious.
- For residential lots greater than 1ac in size with an existing home as of May 1, 2023, on the lot, per UDO 9.2.2.A.1.b.ii code changes (TC-1-23), your maximum additional impervious is limited to 5% of the permeable area on your property. Permeable area includes grassy or otherwise landscaped areas.
- For undeveloped residential lots greater than 1ac in size, the maximum impervious limit is 5% of the total lot area. If you are proposing impervious surfaces above the 5% maximum, you will need to comply with the traditional stormwater requirements related to nutrient management and runoff (UDO 9.2.2B-H).
Grandfathered lots that are 1ac or less in size are able to exceed their impervious limits providing a residential flood study prepared by a professional engineer or proposing a stormwater control measure designed by a professional engineer that meets UDO 9.2.2.A.1.4.b.
If you have questions concerning your property’s impervious surfaces please reach out to Stormwater.Impervious@Raleighnc.gov for more information.
2. Residential Lots Created After May 2001
If your residential lot was created after May 2001, your subdivision was likely approved after the creation of the City’s original Stormwater Management Program. These subdivisions and their residential lots may either have no maximum impervious limits or specific impervious limits assigned on a per lot basis. This information may be found on a surveyor of the property or on the subdivision’s recorded plat with Wake County. If you have questions concerning your property’s impervious surfaces please reach out to Stormwater.Impervious@Raleighnc.gov for more information.
