Septic Systems


Septic Systems

When your property uses a septic system for wastewater disposal, you become your own sanitary utility. You own and operate the facilities, maintain them, and must replace them when necessary.  Your wastewater disposal system is the septic system buried under your yard. The septic system treats wastewater that flows from your home or business and disperses partially treated effluent for final treatment as it percolates through the soil.  The ability of a septic system to adequately and safely treat and dispose of sewage depends on the soil and rock conditions under your property and on how well you maintain and operate the systems. 

Area Requirements for Septic Systems


Septic Systems
Septic System with Septic Tank and Drainfields
Source: Thomas H. Miller (MCES)

Under current standards, a septic system for a new building lot must have an initial drainfield and enough area for three reserve or back-up drainfields. These back-up fields are built and put into service only as the drainfield currently in use fails. A typical single-family house needs an area of at least 10,000 square feet (slightly less than one-quarter acre) for the initial and reserve drainfields.

Properties in the Patuxent River watershed, with water supply reservoirs for the Washington Suburban Sanitary Commission, must reserve an additional 70 percent of treatment area. That means a single-family house that needs to reserve 10,000 square feet elsewhere in the County would need to set aside 17,000 square feet (slightly less than two-fifths acre) in the Patuxent River watershed.

Septic systems may not be located closer than 100 feet to any existing or proposed well. In addition, County onsite systems regulations establish other septic system setbacks for site features like steep slopes, stream buffers, and buildings.