GroundRosterColumbia Land ServicesLicensed
| Name | Columbia Land Services |
| License number | MI 188, 2602, 165, 164, 84, 83 |
| License type | Installer ยท Onsite System Maintainer |
| License status | Active - King County certified master installer; Active - King County certified onsite system maintainer |
| Location | Ravensdale, Washington 98051 |
| Phone | (425) 584-7167 |
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What this license covers
- Installation / repair: licensed to build and install septic tanks and drainfields, and to repair or replace failed ones.
- Pumping / cleaning: licensed to pump out and clean septic tanks, service them, and haul the waste.
How to verify this license
We publish this listing exactly as it appears in Washington's official licensing records; we do not vouch for the business itself. Before hiring, look up license #MI 188, 2602, 165, 164, 84, 83 directly with the state, confirm it is still active, and ask for a current certificate of insurance.
Source: King County Public Health - Master Installers (OSS) + King County Public Health - Onsite System Maintainers, last checked 2026-08-19. Verify at the official source.
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