Obtaining septic approval for a piece of property is a critical step in the process of building your home. While a number of regulations may determine many details of the construction, inability to gain septic approval can bring the process to a halt. Familiarity with issues relating to septic system approval can help to insure that the process does not become burdensome and that your septic system is the most reliable and least expensive option possible.
Check Before You Buy
Although uncommon, sites do exist which are unsuitable for septic system installation, and development of these properties cannot take place under current state law. A large number of sites are suitable, but limited for septic system installation. Those limitations can translate into requirements for expensive and elaborate septic systems. Some of these systems can cost in excess of $10,000. Know the site limitations before you buy.
What to Look for in Land
Some land is well suited for septic system installation, and some is not. Site limitations can often be overcome with highly complex, expensive system design. Well suited sites are those with both adequate available area and suitable soils. It is important to consider, not the overall size of the property, but the amount of the area available for septic system installation. Setbacks to wells, surface water, and steep banks must be met by both the primary system and an area set aside for repair of that original system (reserve area).
Suitable soils are well drained and undisturbed. Disturbance of the soil by grading, filling, or compaction limits the soil for effluent treatment.
Drainfields must be placed in deep, well drained soil. Avoid looking in low lying areas or places where water loving plants like alder, rose, cedar, buttercup, or swamp grass are found. Shallow clay, hardpan, or strongly discolored soils, regardless of elevation, have extreme limitations for septic system installation.
Septic System Installation Requirements
Typical septic systems consist of a septic tank and drainfield. The septic tank is usually placed close to the house to reduce problems with solids accumulating in the sewer pipe. Unlike the tank, the drainfield can be located at considerable distance from the tank in order to take advantage of suitable soils. If suitable soils cannot be used with gravity flow from the tank, relocation of the housesite or use of an effluent pump may be necessary.
The drainfield can be installed into gentle slopes as long as the trenches run level, along the contour. The use of a distribution box allows drainlines to be placed at different elevations and still receive equal use.
Drainfield sizing is determined by the number of bedrooms in the house and the type of soils on the property. Coarse, sandy soils require less drainfield than fine, clayey soils. A three (3) bedroom house on a site with loamy sandy soil has approximately 150 ft. of trench 3 ft. wide.
The Application Process
Jefferson County Health Department requires septic system designs for all repairs of new construction. Licensing of designers is done by the state. A list of licensed designers is available at the Department of Licensing website at www.wa.gov/dol
FAQs
QUESTION: “Where can I find information regarding the soils on my property?”
ANSWER: General soil information can be found in the County Soil Survey available from the Soil Conservation Service and local agencies, from the county health department, and from local septic contractors and designers. Many sites have highly variable soils which can be well suited for septic system installation in some areas and poorly suited in others. A person trained in soil analysis can identify the best soils on a site.
QUESTION: “I have hard pan and clay on my lot. What kind of septic system will I need?”
ANSWER: Designers can match septic installations to the limitations of the site. Since simple, reliable, and economical systems can only be used where soils are of high quality, it is worth the time to conduct a thorough assessment of soils throughout the lot in order to find the best available area. In order to do this, it may be necessary to dig a large number of test holes in various locations on the property. Where even the best soils have extreme limitations for septic installations, designs for more elaborate and expensive systems will be necessary. It is important to remember, however, that a few sites do not have any suitable soils and septic installations may not be permitted under current regulation.
QUESTION: “How do I recognize suitable areas foe septic installation?”
ANSWER: A suitable area for septic installations will have deep, well drained, undisturbed soils, adequate area for a primary and reserve drainfield and can meet setback distances from surface water, wells, banks, etc. Sandy loam soils, like those well suited for gardening, are an ideal soil texture. A well drained profile to a depth of at least 48 inches is necessary for the installation of a standard system.
NEED HELP?
No-cost assistance is available in the following ways:
Information on financial assistance which may be available to property owners to repair or upgrade their on-site sewage systems.
General information on septic systems and water quality.
Workshops for understanding, operating and maintaining your on-site sewage system.
