Managing the storm water around a swimming pool and its equipment is one of the most important early planning stages when building an inground pool. The pool and the surrounding concrete decking are creating a large area of impermeability over the ground, which dramatically changes water flow, above and below ground.
Many communities or towns have ordinances requiring a storm water management permit during construction of a swimming pool. This ensures that rogue pool builders aren't causing erosion through untamed storm run-off, possibly damaging the ecology of sensitive ecosystems or watersheds, or flooding neighboring homes, businesses, or public lands.
Pool Storm Water Management Permits
Most of our inground pool kits are under 1000 sq ft of total area, including the pool deck, and storm water or grading plans may not be required in your area. Depending on the location and zoning of your property, the size and location of your planned inground pool, a storm water management permit, plan and fee may be required.
- Total square footage of pool and deck is very large
- Pool is located in a Floodway or Floodplain
- Pool is located in a wetland, or near lake or stream
- Pool is located uphill from neighbors
- Pool is located on or near a hillside
In these cases, as part of the application process, a drainage plan similar to the one shown on the right will be required, to show drainage around the property. It's helpful if your map also shows elevations, but may not be required.
However, the planning for storm water management is a very important step, not only for the health of your pool, but for the health of the environment around your pool, and your neighbors, be they human or animal. A pool can displace a lot of area that was once permeable, but the pool and deck make the surface impermeable and well, the water has to go somewhere!
Plan for the 100 year storm, the once in a lifetime weather event - those days where it rains 6 inches in 24 hours. Or if you are in a floodplain, plan for the river, lake or stream to overflow and flood your backyard (but not the pool!).
Pool Grading Plans
For new pool construction that disturbs or displaces a large amount of surface area, many local counties or cities require a grading plan for pools built in residential neighborhoods.
A grading plan is essentially a plan that shows the finished elevation of the pool and the surrounding land, and also illustrates topographical features, allowing county officials to visualize the run off around the pool.
Your city or county may require a grading plan when the total disturbance area (deck + pool) is greater than "x" amount of square feet. For some counties, this is 5000 sq ft, but can be as low as 2000 sq ft. Many rural or semi-rural areas do not require grading plans or storm water plans.
A pool grading plan can also be required for smaller pools, if the construction process blocks existing waterways, or if the pool is built within a hillside or in a resource protected area near a stream, marshland or floodplain.
Getting Storm water and Grading Maps
You could do it yourself, if you familiarize yourself with the type of document that is required, and you have some freehand drawing skills. Check with your permit office or inspector, some may require documents that are prepared by a draftsman. You can find a local civic engineering firm, landscape architect or engineering/surveying company to do a short study, make a drainage/grading plan and produce professional plans that can also be used by the excavator / grader. Some excavation companies can produce grading plans.
Pitfalls to Avoid
One of the worst installations I came across was a vinyl pool that was sunk down into the back yard, behind the house, with a large hill behind the house. Sandwiched in between the house and pool, storm water had no where to go, and during heavy rain storms it would begin to drip into the pool, until the pool overflowed and began to wash dangerously down the hillside.
In addition to heavy rains, high water tables can also cause trouble. For all swimming pool installations, a good grading plan is necessary to keep high water tables away from the pool. Water needs to run around the pool, and not get trapped up underneath.
Use swales, berms, French drains, retaining walls, terraces, gravel channels, and even dry well dewatering pumps as necessary to avoid trapped water, and keep it moving away from the pool, while at the same time, controlling the outflow.
When you begin planning for an inground pool kit, choose the SPP Pool Experts, who will walk with you every step of the way - from layout to landscaping! Call us today and build your own inground pool!
SPP Pool Expert