How Impervious Surface Limits Can Affect Your Pool Installation in NC

a swimming pool with a metal railing.

Key Points

  • Understanding impervious surface limits is crucial for planning your in-ground pool project in North Carolina, ensuring compliance with local zoning and environmental regulations.

  • Exceeding impervious surface limits can result in regulatory repercussions, stormwater management issues, and potential denial of building permits.

  • Local resources like Raleigh’s iMAPS system and county-specific guidelines are essential for determining your exact impervious surface limit and ensuring your pool project adheres to legal requirements.



Navigating the Waters of Impervious Surface Limits for Your Pool Paradise

Planning to transform your backyard into a personal oasis with an in-ground pool? Wondering how the maze of local regulations regarding impervious surface limits fits into your blueprint for relaxation and fun?

You’re in the right place.

This post will guide you through the complexities of impervious surface limits and their impact on your pool installation project in Raleigh, Clayton, Johnston County and surrounding areas.

By the end, you’ll not only be more informed about the regulatory landscape but also equipped with the knowledge to make your vinyl liner pool installation project a smooth sailing adventure.

Let’s unlock the secrets to seamlessly blending compliance and design, ensuring your pool becomes the highlight of your home without ruffling any regulatory feathers.



What Is An Impervious Surface?

An impervious surface refers to any material that prevents the infiltration of water into the ground.

These surfaces are typically man-made and include materials like asphalt, concrete, stone, and metal.

Because these surfaces do not allow rainwater or melted snow to soak into the ground, the water runs off the surface, often carrying pollutants into storm drains, rivers, and lakes.

The increase in runoff can lead to higher rates of erosion, water pollution, and flooding.

In urban and suburban areas, managing the impact of impervious surfaces is crucial for maintaining water quality and preventing water-related issues.


Here are some examples of impervious surfaces:

  • Roofs

  • Solid Decks

  • Patios

  • Sidewalks

  • Driveways

  • Parking Areas

  • Roads

  • Compacted Gravel

  • Concrete Around an In-Ground Pool



Does a Pool Count As an Impervious Surface?

No, the water body of the pool itself does not count as an impervious surface because it allows for water infiltration and storage.

However, any surrounding hardscaping—like concrete decking or patios—does contribute to your property’s impervious surface calculations.

Knowing your local zoning laws, setback requirements, and impervious surface limits is a crucial pool building consideration.



How Does an Impervious Surface Impact the Environment?

The water cycle is significantly impacted when there are large amounts of impervious surfaces.


The Natural Water Cycle

Places with little impervious surface areas, like a forest, allow rainwater to seep into the ground.

The water is filtered by natural processes as it moves through the ground before it reaches streams and creeks.

This process helps to keep the amount of water in streams and creeks from changing too much or too quickly.


The Impact of Impervious Surfaces

When an area has a lot of impervious surfaces, the water can’t seep into the ground.

The polluted runoff increases, potentially causing more than 5 times as much water to quickly run off the land and into nearby bodies of water.

When more stormwater reaches streams and rivers, the risk of floods occurring increases.

Streams flow faster, which causes the shape of the stream to change due to erosion.

This causes a serious problem with more extreme flooding and damage to wildlife habitats.

At the same time, because there is less moisture in the ground, plants and grass need extra water through irrigation in order to survive.

Studies have shown that local water bodies are less healthy when as little as 10% of an area is covered in impervious surfaces.

When over 30% of an area is covered in impervious surfaces, nearby streams, rivers, ponds, and lakes can be severely damaged.



What Is My Impervious Surface Limit?

The answer to this question depends on your specific location.

The impervious surface limit varies by county, town, and even neighborhood.

Impervious limits are also different for individual zoning districts by each county.

Follow the link to explore other crucial questions to ask before building a swimming pool.



How Do I Find Out My Impervious Surface Limit?

1.First, obtain a current survey of your property.

You’ll need a current survey of your property that includes all of the existing structures, concrete surfaces, sheds, distances to property lines, etc.

Typically, your builder will provide you with a final survey with your home’s closing documents.

Otherwise, you’ll need to obtain a survey from a licensed survey company.

Not only does a survey help you determine your impervious surface limits, it also helps you select the right pool shape for your yard.

2.Next, given the wide variance in limits, obtain your impervious surface area information directly from your local municipal authorities. (Keep reading for links to municipal authorities in your area!)

These two steps ensure that your dream pool project aligns seamlessly with local environmental and zoning laws, paving the way for a smoother installation process.



How Are Impervious Surface Limits Calculated?

During the subdivision approval process for a residential area, a design engineer determined what level of impervious the subdivision would have and whether stormwater devices would be installed for the entire subdivision.

Each zoning district has a maximum impervious surface percentage that is allowed.

A typical calculation for an impervious surface for a property can look like this:

“The percentage of impervious surface is calculated by dividing the surface area of existing and proposed impervious surfaces on the portion of a lot or parcel that is with 300 feet of the ordinary high-water mark by the total surface area of that portion of the lot or parcel that is within 300 feet of the ordinary high-water mark and multiplied by 100.”



What Happens If I Exceed My Impervious Surface Limit?

When you’re dreaming up the perfect backyard retreat in Johnston, Wake, and Harnett County, it’s easy to get carried away with visions of sparkling pools and sun-drenched patios.

However, navigating the rules around maximum impervious surfaces is a crucial step in this journey.

Let’s dive into what exceeding these limits means for your project.

Exceeding your maximum impervious surface limit can lead to a cascade of complications.

Here’s a straightforward look at what might unfold:

  • Stormwater Management Concerns: Surpassing the limit disrupts the natural water flowing process, increasing the burden on storm drains and potentially leading to erosion control issues.

  • Regulatory Repercussions: Property owners may face fines or be required to modify or remove proposed impervious features to comply with environmental regulation.

  • Permitting Problems: Building permit applications might be delayed or denied. Ensuring your plot plan accurately represents your house footprint and any impervious area is critical for approval.



How to Find Out the Impervious Surface Limits for Your Home in Wake, Johnston, and Harnett Counties


Wake County

For single residential lots in Wake County, the upper limit is 30% impervious.

This means that only a third of your property can be covered with materials like concrete, which does not absorb water.

However, subdivisions can range from 6% to 30% impervious depending on the level of stormwater treatment that was installed during development.

Follow the link for more information about Wake County Stormwater Review and Permitting.


City of Raleigh

Raleigh presents a more complex scenario with its five distinct zoning districts, each dictating its own set of rules for the amount of impervious surface coverage.

These regulations can significantly influence your in-ground pool installation plans, with limits ranging from 20% to a more generous 65%, depending on your property’s zoning designation.

Follow the link to view an impervious surface map for Raleigh, NC.

Another valuable resource at your disposal is Raleigh’s iMAPS system.


Johnston County

Johnston County provides information on residential impervious surfaces, also called built upon areas (BUA), restrictions.

Follow the link for more information on when approval from Johnston County is required.


Town of Cary

The Town of Cary has specific requirements for swimming pool locations, pool decking, and pool barriers.

Follow the link for information on the limitations on impervious surface area and density in Cary, NC.


Town of Apex

The Town of Apex regulates the measurements for setbacks, lot sizes, and other specifications for buildings.

Pools, both above-ground and in-ground, can be located no closer than 5′ from the side or rear property line.

Follow the link for information about impervious limits in Apex, NC.


Harnett County

For information about Harnett County construction permits and inspections, see the Harnett County website.


Town of Holly Springs

Contact either the town planning department for Holly Springs or Wake County to find out what the impervious surface limits are for your subdivision.



Discover How Prestige Pools of NC Simplifies Pool Installation

Navigating impervious surface regulations might seem daunting, but understanding them ensures your pool project progresses smoothly and sustainably.

Our guide has armed you with the knowledge to approach your installation with confidence, clarifying key considerations like zoning regulations and environmental impacts.

With Prestige Pools of NC, you’re not just building a pool; you’re ensuring it complements your property without legal hassles.

Our experts are ready to turn your backyard dreams into reality, adhering to all local guidelines.

Ready to take the plunge?

Fill out our contact form today, or give us a call. Let’s make your pool project a resounding success!