WAC 372-36-030
Domestic sewage rules. (1) Municipal and
community. (Including school and industrial installations):
(a) The discharge of raw sewage is prohibited under any
circumstances.
(b) The discharge of sewage treatment plant effluent into
canals used for irrigation or stock watering is prohibited.
(c) The discharge of sewage treatment plant effluent into
drains, wasteways, or reservoirs, from which water is
subsequently reused in canals and laterals is prohibited,
except by specific approval where special circumstances may
require such discharge.
(d) The disposal of sewage treatment plant effluent by
land application methods is prohibited in locations where such
disposal would adversely affect surface or groundwater
withdrawn for domestic purposes. Discharge at extreme depths
is prohibited.
(Note:
Rules and regulations of the state board of health prohibit irrigation of certain crops with sewage plant effluent.)
(e) The minimum degree of treatment shall, in any case,
be at least the equivalent of primary treatment and
disinfection of the effluent.
(f) Additional treatment, of a degree to be determined
for each case, shall be provided where specific approval is
granted for discharge to drains, wasteways, or reservoirs.
(g) Additional treatment, of a degree to be determined
for each case, shall be provided prior to disposal by land
application methods when necessary to prevent possible
contamination of ground and surface waters, or creation of a
nuisance.
(h) Notwithstanding (a) through (g) of this subsection,
the degree of treatment, the provision for disinfection and
method of disposal shall be a matter for the determination and
approval of the department of ecology for each individual
case.
(2) Individual farm unit, household or other source of
domestic sewage not covered by subsection (1) of this section.
(a) No raw sewage or septic tank effluent shall be
discharged to any canal, reservoir, drain or wasteway.
(b) Households, farm units, schools, small business
concerns or other sources of domestic sewage involving a
limited number of persons shall provide sewage disposal
facilities as prescribed by the county health department of
the county in which the source is located.