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Septic Services in Spokane, WA

Spokane County County · Pop. 228,989

Spokane sits in eastern Washington's Inland Empire, a region with dramatically different soils and climate from the wet west side of the Cascades. Ritzville silt loam and loess-derived soils in the Palouse uplands south of Spokane provide better natural septic system conditions than most of western Washington, with deeper soil profiles and lower seasonal groundwater. However, Spokane County faces a unique challenge: the Spokane Valley-Rathdrum Prairie Aquifer, a sole-source drinking water aquifer that provides water to over 400,000 people. USEPA has designated this aquifer as a sole-source aquifer under the Safe Drinking Water Act, meaning septic systems installed above it must meet enhanced standards. The county has operated a voluntary and mandatory Septic Tank Elimination Program (STEP) for decades, converting older failing systems near the Spokane River to sewer where feasible. Eastern Spokane County's shallow granite soils require engineered system designs.

Septic Providers in Spokane (7)

SS

Scott's Septic Service provides professional septic services in Seattle, WA and surrounding areas. Contact them for septic pumping, repair, and inspection services.

Septic PumpingSeptic RepairSeptic Inspection
(253) 261-3453 View Profile

Services in Spokane

Drain Field Repair

$2,000 – $15,000

Grease Trap Pumping

$200 – $800

Septic Inspection

$300 – $600

Septic System Installation

$3,500 – $20,000

Septic Tank Pumping

$275 – $600

Septic Repair

$500 – $5,000

Well Drilling

$6,000 – $25,000

Well Pump Repair

$300 – $3,000

Well Water Testing

$50 – $500

Well Water Treatment

$500 – $8,000

Septic Service Costs in Spokane

Service Average Cost
Septic Tank Pumping $225 - $400
Septic System Installation $7,000 - $18,000

Soil Conditions

Spokane County soils include the Ritzville silt loam on the Palouse uplands—a deep, well-drained wind-deposited loess with moderate permeability. Latah and Spokane sandy loam soils dominate near the Spokane River corridor. Dragoon gravelly sandy loam and Spokane cobbly sandy loam are shallow soils over granitic bedrock in eastern Spokane County foothills with variable permeability.

Ritzville silt loam (USDA series) is a deep, well-drained loess soil covering much of the Palouse uplands in southern Spokane County. It has moderate permeability (0.6 to 2.0 in/hr) and is generally suitable for conventional gravity systems. Dragoon gravelly sandy loam is a shallow soil over granitic bedrock common in eastern Spokane County foothills, requiring careful evaluation for depth to bedrock. Latah silt loam in valley bottoms has slow permeability and seasonally high groundwater, typically requiring mound systems.

Water Table: Groundwater depth ranges from 15 to 50 feet in most Spokane area uplands. The Spokane River floodplain shows seasonal groundwater at 3 to 8 feet. The Spokane Valley-Rathdrum Prairie Aquifer underlies much of eastern Spokane County at depths of 10 to 50 feet.

Local Regulations

Spokane County Environmental Services administers OSS permits under WAC 246-272A. Spokane County designates a Sensitive Aquifer Management Area (SAMA) over portions of the Spokane Valley-Rathdrum Prairie Aquifer, requiring enhanced treatment systems in these zones. New systems within 200 feet of the Spokane River require pretreatment to secondary treatment standards. O&M agreements are required for all alternative systems. Spokane County's STEP program may provide conversion to sewer as an alternative.

Spokane County Environmental Services administers OSS permits under WAC 246-272A for unincorporated areas. City of Spokane is largely sewered, but outlying areas require permits. Spokane County requires a licensed designer evaluation, construction inspection, and final approval before backfill. Alternative systems require O&M agreements. The county operates a Septic Tank Elimination Program (STEP) for properties near the Spokane River.

Frequently Asked Questions — Spokane

What is the Spokane Valley-Rathdrum Prairie Aquifer and how does it affect septic systems?
The Spokane Valley-Rathdrum Prairie Aquifer is a sole-source drinking water aquifer designated by USEPA that extends beneath Spokane Valley and into northern Idaho. It supplies drinking water to over 400,000 people. Septic systems installed above this aquifer must meet enhanced treatment requirements under Spokane County's Sensitive Aquifer Management Area (SAMA) rules to protect groundwater quality.
What is the STEP program and does my property qualify?
Spokane County's Septic Tank Elimination Program (STEP) is a program that converts properties with failing or high-risk septic systems near the Spokane River and other sensitive areas to a low-pressure sewer system. Eligibility depends on proximity to existing sewer infrastructure and funding availability. Contact Spokane County Environmental Services to determine if your property is in a STEP service area.
Is Spokane's eastern drier climate better for septic systems than western Washington?
Generally yes. Spokane's semi-arid climate with 16.7 inches of annual precipitation means soils are not continuously saturated like western Washington's glacial till areas. Drainfields in Ritzville silt loam or similar loess soils benefit from the dry summer season. However, Spokane still has frost depths of 24 to 30 inches, requiring freeze-resistant access components.
How deep is frost in Spokane and how does it affect my septic system?
Spokane typically experiences frost depths of 24 to 30 inches from December through February. Properly designed systems account for this by placing distribution pipes at adequate depth and providing insulated covers over risers and pump tanks. Access risers should extend above grade to allow winter pump-out without excavation. Systems installed before modern standards may not have adequate freeze protection.
What are typical septic pumping costs in the Spokane area?
Septic tank pumping in the Spokane area typically costs between $225 and $400 for a standard residential tank. Prices vary based on tank size, access difficulty, and contractor. Most Spokane area septic tanks should be pumped every 3 to 5 years. Tanks located in Sensitive Aquifer Management Areas may be subject to more frequent inspection requirements.

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