Guam EPA presents new on‑site wastewater rules requiring NSF‑certified 'type 4' systems, operating permits

Guam Environmental Protection Agency staff presented draft amendments to the agency's on‑site wastewater disposal regulations Thursday that would require higher‑performance treatment systems in specified areas and add ongoing operating permits and construction standards.

The draft rule package, developed over several years and presented by Brian (former Guam EPA staff, presenter), implements amendments to 22 GCA chapter 12 and the toilet facilities and sewer connection law (10 GCA chapter 48) and carries out provisions of Public Law 37‑105 and Public Law 38‑7, the presenter said. The rules would require NSF‑certified ‘‘type 4’’ nitrogen‑reducing systems in some locations, mandate site soil (percolation) tests for all on‑site systems, require watertight septic‑tank construction, and add operating permits for certain system types.

The amendments would require type 4 systems — third‑party certified under the NSF program cited in the presentation — to achieve a minimum 50% reduction in nitrogen loading to the aquifer and would require operating permits renewed every two years for type 4 systems and mound systems and…