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One of the most common questions I get asked is;

How much does a new septic system cost?

This is a very difficult question to answer, since not all septic systems are created equal.

Septic systems are designed to the specific soil types, water tables and restrictive layers on a given site. They are bound by the Washington State Administrative Code and Regulations, Standards and Guidelines of each system.

So in laymens terms; Sites with bad soils and bad water tables are going to have tighter restrictions, which make them more complicated and expensive. Septic systems with good soils and deep water tables are less restricted, less complicated and usually cheaper.

Septic systems in Whatcom and Skagit county are sized based on the number of bedrooms, soil type and water table.

If you would like a more accurate estimate for your site, please contact us and I would be happy to consult with you.


Septic Design Fee: The amount a designer or principle engineer will charge to do site work and design a system for a specific site.

Whatcom County Health Department Review Fee: The amount the health department will charge to review the plan, make a site visit and approve the design.

$1,026.91 (as of 01/01/2023)


Please call if you'd like a site specific consultation.

Conventional System - A pipe carries all wastewater from your home and it's sent to a storage tank where the solids and water are separated. The solids form sludge, while the water is sent to the drainage field where it is slowly released into the soil for filtration.

Gravity System - A conventional system which uses gravity to force the wastewater out into the drain field. These types of septic systems use gravel as a filter.

Underground Pressure Distribution System - A conventional system which involves the use of a pump. The pump forces the wastewater out of the system to drain more effectively, so most new conventional systems use this method.

Mound Septic System - This system uses elevated ground in some cases when there is not adequate soil for a conventional system. The drainage is directed to an area with a higher elevation, so that the water must filter through more soil or sand before reaching the groundwater.

Aerobic Treatment Unit System - This type of alternative septic system uses oxygen which helps to break down the solids much faster, and results in cleaner water being discharged from the system. These systems do not experience septic system problems as often, but they must be closely supervised and maintained at all times.

ATU to Underground Pressure Distribution

ATU to Mound Septic System

Drip Irrigation System - This is one of the types of septic systems that are very flexible, and these systems can be placed in many different types of soil. When you have a drip irrigation system, the water is slowly distributed evenly through the drainage field. This makes sure the soil will not become saturated and the system is more effective.

ATU to Drip Irrigation system

Membrane Bio Reactor - The newest form of system approved in Washington State. This system involves the filtration of effluent in the second compartment of the septic tank using a membrane bioreactor unit that forces waste water through microscopic pores on a membrane and leaves a highly treated effluent to be distributed to the drain field. This unit can treat up to level A without UV disinfection and is good for hard to treat lots with environmetally sensitive areas.

Glendon BioFilter System - This proprietary alternative septic system uses many layers of alternating sand and gravel placed in a container which is watertight and sealed. The wastewater is pumped into the box on the bottom, and the effluent must work through the various layers to the top of the box to reach the soil.

Ultraviolet Disinfection Systems - This is another of the disinfectant types of septic system and with this system ultraviolet radiation is used to treat and clean the water. When this radiation is absorbed by the microorganisms in the effluent and solids then the microorganisms cannot reproduce rapidly. A UV light is added to most all ATU systems to polish effluent.

Included in the cost of ATU systems.

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