We Moved a Family's Drainfield Out From Under Their New Pool in Simpsonville, SC

A family in Simpsonville built a new in-ground pool with an attached spa and lined up a pool house to go in next. BKF Builders, a client we've worked with before, called us when the septic didn't square with the plan. Alex mapped the existing system and found the drain lines running the length of the yard and passing directly beneath the new pool shell.

The existing drainfield ran off the tank toward the rear of the property, and the newly poured pool sat squarely on top of a stretch of it. The required drainfield size depends on the home’s design flow and the soil conditions documented in the permit. On this property, the conflict affected an active section of the field rather than a single pipe near the pool. A working section of the field the household depends on was now buried under an impermeable concrete shell.

The drainfield is the final and most important stage of treatment. Effluent leaves the tank, trickles through the gravel bed, and enters a thin biologically active layer of soil where oxygen-fed bacteria break down the remaining organics before anything reaches groundwater. The drainfield depends on unsaturated soil with enough oxygen to support wastewater treatment. A pool cannot be installed over it because construction can damage the trenches and compact the soil, while South Carolina also requires a 15-foot separation from an in-ground pool.

Under South Carolina Regulation 61-56, the septic system must generally remain at least 15 feet from an in-ground pool and 5 feet from a property line. The approved permit may require greater separation. The 15-foot pool setback applies to the septic tank and drainfield laterals, although solid conveyance piping is excluded. Once the pool was installed over the field, the system no longer met the required separation from the pool.

The existing concrete tank was structurally sound, so the crew pumped it and kept it in service. Only the drainfield needed to move. Alex rerouted the full drainfield to the back of the lot, well clear of the pool and the patio. Alex installed a four-inch perforated distribution pipe and approved aggregate to the dimensions shown on the SCDES permit, then covered the aggregate with permeable geotextile material to keep backfill from entering the stone. The new field was sized and laid out according to the soil conditions documented for this property and the requirements of the SCDES permit. Alex set the new field so the planned pool house has clear ground to be built on later. When the family is ready for it, no pipe has to move a second time.

The full relocation cost $8,700 and was paid for by card. Moving a drainfield is close to building a new one, with fresh trenches, new pipe and stone, and the excavation to place it all in heavy Upstate clay. Drainfield work in South Carolina generally runs $5,000 to $15,000, with clay soils pushing jobs toward the upper end. At $8,700, this relocation came in near the middle of the range while also protecting a finished pool and clearing the way for the pool house. Finding the conflict later could have required more extensive excavation and additional work around the finished pool.

A pool and a septic system end up sharing a lot of Upstate backyards, and these are the questions that come up on almost every relocation we run for a family adding one.

Nobody plans their backyard around the septic system, and they shouldn't have to. Our job is to put it somewhere it works quietly for decades so the family never thinks about it again. This one now sits at the back of the lot, correctly set back and able to breathe, while the pool and the pool house get the yard they were meant to have.