What is the primary regulation requiring pressure distribution for certain conditions?

The primary regulation requiring pressure distribution under certain conditions is WAC 246-272A. This regulation outlines the standards for the design, installation, and operation of on-site sewage systems in Washington State. It specifically addresses the need for pressure distribution systems in specific situations where standard gravity-fed systems may not be adequate, such as areas with high groundwater levels, shallow soil depths, or other challenging site conditions.

WAC 246-272A is essential for ensuring that septic systems function effectively, minimize environmental impacts, and protect public health. Pressure distribution helps to evenly disperse effluent over a larger area of the soil, improving treatment efficiency and reducing the risk of system failure. By adhering to these regulations, installers can help prevent issues like soil saturation and surface flooding, which could occur if effluent is not dispersed properly.

While EPA Guidelines and Federal Wastewater Standards offer a broader framework for wastewater management and treatment, they do not specify the conditions under which pressure distribution is required to the same extent as WAC 246-272A. Local Health Codes may also incorporate elements of these regulations or supply additional requirements but are often guided by the overarching state regulation to ensure uniformity across the region.