How Much Does Septic System Installation Cost in Seattle, WA?
Average septic system installation costs in Seattle range from $17,017 to $23,023. Get a free, customized estimate below.
Septic System Installation Cost Breakdown — Seattle, WA
| Item | Unit | Qty | Unit Price | Total |
|---|---|---|---|---|
| Septic Tank (1500 gal) | each | 1 | $4160.00 | $4160.00 |
| Drain Field & Gravel | linear ft | 200 | $45.50 | $9100.00 |
| Excavation & Backfill | lump sum | 1 | $2340.00 | $2340.00 |
| Labor & Permits | hr | 40 | $110.50 | $4420.00 |
| Estimated Total | $20,020.00 | |||
* Prices are estimates based on Seattle market rates. Actual costs may vary based on project specifics.
Estimate
Ref ID: EST-2026-3YG8
Date Issued
May 6, 2026
Client
Project Details
Site Address
Start Date
End Date
Scope of Work
Materials
| Material Specification | Units | Amount | Ext. Total | |
|---|---|---|---|---|
$ | $4,160 | |||
$ | $9,100 | |||
$ | $2,340 | |||
$ | $4,420 |
Labor
| Service Specification | Type | Hrs | Rate | Ext. Total | |
|---|---|---|---|---|---|
Craftsmanship Guarantee | $ | $600 |
Contractual Agreements & Conditions
Total
$20,620
Draft
Frequently Asked Questions — Septic System Installation in Seattle
How much does septic system installation cost in Seattle, WA?
The average cost for septic system installation in Seattle, WA ranges from $17,017 to $23,023, depending on project scope, materials, and labor rates. Seattle costs are above the national average due to higher labor and material costs in the region.
How do I get a free septic system installation estimate in Seattle?
Use Brixor's free online estimate generator above. Enter your project details, customize line items for your specific needs, and download a professional PDF estimate instantly. No signup or credit card required.
What factors affect septic system installation costs in Seattle?
Key factors include project size and complexity, material quality, labor rates in Seattle (WA), permit requirements, accessibility of the work area, and seasonal demand. Getting multiple estimates is recommended.