Even the steepest hill needs a safe driveway down
The maximum driveway slope is 25%.
Most places have a maximum slope between 10% and 18%.
Any slope above 15% is considered steep.
Look at local requirements to see what your municipality allows.
If you live on a hill, then you may be wondering just how steep your driveway can be before it becomes a problem. But knowing the maximum driveway slope or grade you can have gets a little confusing depending on where you live, local regulations, climate, and more. Let's break down the maximum driveway slope once and for all.
A driveway slope is the percentage that your driveway rises over 100 feet of pavement. For example, if you have a 10-foot rise in elevation per 100 feet, that’s a 10% slope. Your driveway should gradually rise as it goes toward the house, with your home sitting at the highest point.
A driveway slope helps prevent rainwater from collecting around the perimeters of your property during a storm. If you have a negative slope, this can cause structural, foundational, or interior damage to your home.
In some climates, having too steep of a driveway slope can cause your vehicle to slip and slide down the driveway in freezing or rainy weather. That's why most municipalities have their own guidelines to ensure homeowners take safety into consideration. Every region is different, so what applies to one city may not apply to another location.
The maximum driveway slow is 25%, but most places don’t allow for anything over 20%. Generally speaking, a maximum slope for residential driveways is location-dependent and falls somewhere between 10% and 18%, with 15% or higher considered to be a very steep slope.
While it's important to check with your local and state regulations when it comes to your driveway’s maximum slope, you'll still want to be aware of factors that could impact the safety of the driveway's gradient beyond general standards. Here are some of the biggest driving factors:
The type of driveway material you have could impact how well your driveway handles a steeper slope. Surface traction can make the same slope on a sunny, dry day a completely different story after rain or ice. If your area allows for driveways with a slope of 15%, this may be the maximum slope for permeable pavements—not for driveways with impermeable pavements like concrete.
Where you live can mean all the difference between a steep driveway and one that needs local grading services before you can lay pavement. If you don't have a long driveway, then a steep driveway slope may not be possible. There needs to be enough space toward the bottom of the driveway for cars and trucks to exit without damaging the bottom of the vehicles.
Some regions are stricter than others when it comes to driveway slopes. Areas that experience icy weather or frequent storms may have a lower maximum driveway slope to help protect residents from losing traction, whereas arid and mild climate zones may have more wiggle room for steeper driveways.
Safety is the most important factor when it comes to having the right driveway slope. Here are some tips on how to fix your driveway slope for a safer driveway:
Use permeable pavers instead of impermeable pavement for added traction.
Install a ramp at the end of your driveway to avoid undercarriage damage.
Hire a driveway paving company near you to pour resin on the surface of your driveway for extra grip.
Put speed bumps on your driveway to reduce slipping.
Regrade your driveway. The cost to repave a driveway is around $6,800 on average.
The best steep driveway material is permeable pavers filled with gravel or crushed stones. Plastic, rubber, and concrete pavers all work to allow water to run down your driveway without washing away and eroding your driveway. These paver materials also do well with ice and snow, unlike brick or concrete pavers. You can also install a driveway retaining wall to help prevent pavers and gravel from shifting over time.
While some areas may allow for a slope of up to 20%, this is often the maximum slope for driveways, with a few exceptions of up to 25%. Other regions may have a maximum of 12%, 15%, or 18%, so check with your local building department to ensure you’re laying a driveway that is up to code for your location.
An ideal driveway gradient is between 2% and 5%. Anything lower than 1% or higher than 15% can cause problems for your car or property. A driveway with less than a 1% slope increases your likelihood of flooding and water damage, while a driveway with a 15% grade or higher can be too steep for safe traveling.
Driveways should be sloped with a minimum 2% slope—anything lower will cause precipitation and runoff to collect. A 2% slope is the equivalent of a 2-foot rise over 100 feet. One quick way to check the integrity of your driveway’s slope: no more than four inches of water should collect on the surface longer than 15 minutes after rain.
