Experience
We have over 20 years of experience installing Commercial and Private septic systems throughout Alaska and Washington.
We are certified to install most Proprietary Advanced treatment systems such as Glendon, OSCAR, Advantex and others.
We are a Preferred Septic Installer for the US Government in Western Washington.
Our Preferred Septic Designers:
Advanced Septic Design, Travis Buck, 360-433-5476
Jim Hunter and Associates, Adam Hunter, 360- 753-1226
Gravity / Conventional System
A gravity system was the standard in days past. It is fairly rare to have gravity systems installed today due to current health codes but they do still occur if conditions are met.
Average Price $7500 +/-
Basic Pressure Septic System
These are the step up from gravity systems. They have all the same components as a gravity with the addition of another tank (pump chamber), a pump, electronic controls and pressure pipe in the drainfield. The drainfield is trenches. The majority of the systems installed is this type.
Average Price $10,000-$15,000
Pressure Bed Septic
Same as the basic pressure but the drainfield is a bed of sand with a layer of filtration chambers or drainrock.
Average Price $10,000-$15,000
Intermittent Sand Filter
This system places a Sand filter in between the pump tank and the final drainfield. This technology is used on sites with shallow soil conditions where treatment must be
accomplished before the effluent is discharged into the soil.
Average Price $19,000 - $25,000
Sand Mound
Used when the site does not have suitable soils for traditional septic systems. There may be too much clay to allow the water to seep through at the proper rate, or the water table may be too high. The liquid is then pumped from the chamber to pipes buried in a mound of sand built on the original soil surface. This system provides a layer of suitable soil thick enough to ensure adequate time and distance for proper treatment of the waste water. Vegetation growing on the mound helps to evaporate some of the liquid. This is particularly important in areas with shallow water tables.
Average Price $17,000 - $25,000
Aerobic Treatment Unit (ATU)
ATUs use oxygen to break down organic matter, much the same as municipal wastewater treatment systems, but in a scaled-down version
Average Price $17,000 - $20,000
Proprietary Systems
Glendons, NuWater, Oscars, Orenco...... These are spec'd out when conditions and soils are particularly difficult. They tend to be a bit more complicated to install and generally require installer certification from each manufacturer.
Average Price $17,000 - $30,000
Mills General LLC
106 Norton LN
Chehalis, WA 98532
360-259-5786
jmills@mills-general.com
WA Lic # MILLSGL832OO
About Us
Mills General LLC is a full service excavation contractor in Chehalis Washington specializing in Septic Installation, Demolition, Site Preparation, Driveways, Land Clearing, Dump Trucking, Water & Sewer Line Installation, Grading and Underground Utility Installation and Repairs.
We service Lewis County, Cowlitz County, Thurston County, Grays Harbor County, Pacific County and surrounding areas.
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