Beyond gravity flow
Alternative and complex systems, without the sales language
If SIPH or DEQ says a standard drainfield will not fit your soil or groundwater, the next step is a system with a published design in Idaho’s Technical Guidance Manual—not a homemade extra trench. Alternative systems cost more to install and they cost every year after that.
Extended treatment package systems (ETPS)
DEQ describes ETPS units as manufactured mechanical devices that provide secondary treatment before effluent reaches a drainfield. They show up where soils are shallow or very coarse, groundwater is high, or an NP evaluation says extra treatment is required. They need electricity. Turning the power off is not a winter energy-saving tip; DEQ says it creates extra operation, maintenance, and monitoring costs.
Idaho requires at least one operation-and-maintenance event per year, plus monitoring so effluent meets 45 mg/L TSS and 40 mg/L CBOD5 (and nitrogen limits when those apply). A certified service provider does that work. An annual report is due to the health district by July 31. The property owner is the person on the hook if the report never arrives.
Before anyone pumps an ETPS tank, DEQ’s pumpers’ manual says to involve the service provider. These units are not a 1,000-gallon concrete box with a lid.
Other alternative and complex work
Pressure distribution, sand mounds, proprietary wastewater treatment systems, lagoons, and similar designs generally require a complex installer permit. A basic installer license is not a discount complex license.
Large soil absorption systems
At 2,500 gallons per day or more—schools, clusters of homes, some commercial sites—Idaho calls the system an LSAS. Expect an NP evaluation, an Idaho-licensed professional engineer, DEQ plan and specification review, a complex installer, inspections by SIPH and DEQ, and an annual operation and maintenance report to both agencies.
Homeowner-installed systems
DEQ allows a homeowner to install a standard/basic system on their own property with no hired help after the permit is issued. That exception does not cover complex systems, and it does not cover hiring an unlicensed friend with a backhoe. If anyone besides the owner is installing, they need the right installer permit and bond.