Clean Water
Septic Installations

Licensed on-site septic system installer

Serving Whatcom and Skagit Counties

Coast Construction is a licensed on-site septic system installer for Whatcom and Skagit Counties. Our crews receive regular training through the Washington On-site Sewage Association. You can depend on our experienced technicians to install your on-site septic system to local Health Department standards. Coast Construction is further certified by the Manufacturer on Whitewater, Advantex, Fast Systems, Geo Flow, and Glendon Bio-Filter, for the installation of Conventional Systems, Sub Surface Drip Systems, (ATU) Aerobic Treatment Systems, Pressure Systems, and Sand Filter Systems.

Septic Design Approved?

If you have an approved septic design, we can provide you with an estimate.

Need Septic Design?

HERE is a full list of Septic Designers in Whatcom County.

OSS (On Site Sewage Systems)

  • Glendon Bio Filter
  • Oscar Systems
  • NU Water
  • White Water
  • Drip Systems
  • Gravity Systems
  • Infiltrators
  • AdvanTex
  • New installation
  • Connect City Sewer

Owners Manuals

The Do’s and Dont’s of Septic Systems

Coast Construction has provided you with the following Do’s and Do Not’s list to help you maintain the long life of your system and to minimize maintenance costs.


  • Flush only toilet paper and what has passed through you first.
  • Know where your septic is, let it breathe, and protect it.
  • Inspect your tanks and field annually or to manufacturer’s specifications, and perform any maintenance required.
  • Clean septic tank outlet filter and/or pump filter as needed.
  • Use water wisely to reduce the risk of water overloads.
  • Avoid using your garbage disposal.
  • Use phosphate-free detergent.
  • Follow manufacturer’s specifications regarding irrigation, planting, and landscaping.
  • Fix all leaking faucets and toilets as soon as possible to prevent over watering of your system and a high-water alarm.
  • Direct runoff from roofs, streets, driveways, and adjoining properties away from the drainfield and reserve area.
  • Keep septic-tank lids easily accessible and watertight.
  • Keep drainfield area and inspection ports accessible.
  • Locate as-built for your system, or map location of all system components.
  • Keep accurate, detailed records (inspections, pumping, repairs, servicing professionals, etc.).



  • DO NOT use tank additives or “miracle” system cleaners.
  • DO NOT use the toilet as a wastebasket.
  • NO diapers, cigarette butts, coffee grounds, tampons, condoms, grease, oils, papers other than toilet paper, plastics, or any other non-biodegradable material.
  • DO NOT dispose of paints or hazardous materials.
  • DO NOT wash grease and oils down the sink no matter how much hot water chases it.
  • DO NOT discard medications (like antibiotics) or antibacterial products down drains.
  • DO NOT drive or park heavy vehicles over the drainfield or reserve drainfield area.
  • DO NOT compact soils of drainfield or reserve in any way.
  • DO NOT cover the drainfield or reserve in any way other than what is recommended by the manufacturer.
  • DO NOT grade, level, fill, or cut drainfield or reserve area.
  • DO NOT plant deep-rooting plants, especially trees and shrubs, in the drainfield or reserve area.
  • DO NOT run storm drainage into the septic system.
  • DO NOT drain water from hot tubs into the system.
  • DO NOT install sprinkler systems in the drainfield.
  • DO NOT allow large animals, (cows, horses, etc.) to enter the drainfield or reserve area.

Call us or schedule a
Free Site Visit Today