Can You Build Over a Septic System?

building over a septic system, structure septicAt some point, you might decide to remodel the exterior portion of your property. This could entail building a structure over the septic system or leach field. Is this okay, or will it impede the system in any way?

We Don’t Recommend Building Over a Septic System

While not prohibited and certainly doable, we don’t advise building any structures directly over the system. Ideally, you don’t want to put any immense weight on the soil that rests above the pipes. Weight causes the soil to compact, which decreases its ability to absorb effluent. Compaction also strips the soil of oxygen, which is required for the microbes to break down the waste.

In addition, any structure, such as a patio or shed, can place undue stress on the septic system, causing the pipes to collapse. We have seen this time and again during septic inspections.

Also, consider that a structure makes it more difficult for technicians to access the pipes for repairs or new installations.

If You Choose to Build Over a Septic System

If you still insist on adding a structure over the system, then follow these tips:

  • As a general rule, the weight of the structure should not exceed 20 lbs per square foot.
  • You must include a hatch, so technicians can access the opening when conducting a septic pump inspection.
  • Check with your city jurisdiction; some municipal ordinances require a permit to erect structures over a system. Verify whether local codes permit hardscapes.
  • If you plant vegetation, limit it to shallow-root herbaceous plants.

We Maintain all Septic System Types

Even the most skilled technicians will struggle to treat your system if a structure lies over it. Please keep this in mind if you decide to proceed with renovation plans. Give Woodinville Septic Service a call before building over a septic system.

Residential Septic System Maintenance

Serving Woodinville, Redmond, Kirkland, Bothell, Mountlake Terrace, Bellevue, Sammamish, Duvall, Issaquah, Snoqualmie and more