On-Site Sanitation Frequently Asked Questions

I am thinking about buying a piece of property outside city limits. I am wondering if the property has an approval for a septic system. How do I find out?

If you have the owner’s name or property address, we can do a query to find out the township, range, section, and taxlot. Our files are organized by T-R-S taxlot dating back to 1968. In some cases, the owners may have not applied for a septic permit, so we may not have any record of a site evaluation being done.

What is a site evaluation ? How long does it take?

A site evaluation is an evaluation of the soil type, soil structure, soil permeability, and a general site description of the topography – slope, aspect, use, etc. A site evaluation will define the approved area and repair area for a septic system. A typical approved site is approximately 10,000 square feet. An approved site does not expire unless the site has been disturbed by excavation or fill. If you were to fill out an application, pay the fee, submit a plot plan, and arrange for a digger within a few days, then the process would take approximately 1-2 weeks depending on demand. It is best to have the field staff there when the digging is occurring to locate the best site.

I have bought a piece of property that has an approval for a septic system. What does this mean?

It means that a piece of your property has had a site evaluation to determine soil characteristics. Now that soil characteristics have been defined, you can apply for a septic installation permit. In some cases, a permit cannot be issued until land-use approval by the Planning Division.

I am building a new home on a piece of property out in the country. What is required in terms of a septic system? Where does the septic system go?

Septic system requirements are based on soil characteristics and the number of bedrooms in a house. Each bedroom in a house accounts for 150 gallons of wastewater. For each 150 gallons, about 150 feet of drainfield is needed based on soil type, slope, etc. A typical septic system design has a minimum of a 1,000 gallon septic tank with approximately 450 linear feet of drainfield. The drainfield must be placed in the approved area by a site evaluation.

I am interested in buying an existing home on acreage out in the County. How do I find out about the condition of the septic system?

Provide us with the owner’s name or property address and we can query the township, range, section, and taxlot. With this information, we can see if permits, installations, and inspections have been done in the past. Usually this information will tell us the general location of the septic system and the size, age, and construction materials. If the septic system has been pumped recently, the condition of the tank inlet and outlet and baffles can be known. A thorough field visit will indicate any drainfield problems.

I am replacing an existing old home with a new home. Can I hook up to the existing septic system?

It depends on the condition of the septic system. If the system is less than 5 years old, then an Authorization Notice is issued after a record review is done. If the system is older than 5 years, then a field visit and record review is required to insure an operating system. Sometimes it is necessary to repair or alter the septic system to accommodate additional wastewater.

I am building a new shop. I plan on putting a bathroom in the shop. Can I hook up to the existing septic system?

It depends on the existing septic system size and condition. An Authorization Notice is required for a record and field review. If the additional wastewater does not exceed 50 percent of the design flow, then the existing size does not need to be altered unless the field visit indicates drainfield problems. If the shop will have an independent drainfield, then a typical shop will require approximately 150 linear feet of drainfield.

What information must be submitted in order to get a septic permit?

  1. A site evaluation approval.
  2. Completed septic permit application.
  3. Plot plan to verify site feasibility.
  4. Land-use approval from the Planning Division.
  5. Permit fee.

Who can install a septic system?

An Oregon Department of Environmental Quality licensed installer or a well-informed property owner.

How do I take care of my septic system? When should the septic tank be pumped?

All septic systems are slowly failing. As time goes by, small particles from wastewater begin to clog the drainfield. In order to slow this process, it is best to use an outlet filter on the washing machine and septic tank to prevent lint and large particles from entering the drainfield. Do not dispose of anything in the toilet except for human excrement and toilet paper, do not use a garbage disposal unit, conserve water as much as possible, and use biodegradable chemicals for cleaning. Septic tanks allow settling of larger particles. Some particles break down, others do not. This accumulation is called sludge. Sludge accumulates at different rates for different households. This sludge needs to be removed periodically or it may enter the distribution pipes and drainfield. This will cause premature failure. Septic tanks on average should be pumped every 5 years. Remember, the greater the input, the more often the tank will require pumping.

How long should a septic system last?

Average life for septic systems range from 20-30 years. The system could end sooner or last longer depending largely on water usage, pumping, and soil characteristics.

What needs to be done if my septic system is backing up and needs repairs?

  1. Check the sludge level – the tank may need to be pumped.
  2. Check the distribution box or drop box for clogging or damage.
  3. Have a licensed pumper or installer check the system.
  4. Contact the County Sanitarian for information on the location of the boxes and drain lines.
  5. Complete a septic permit application to apply for a repair permit or alteration permit.

What is a capping fill septic system? What is a sandfilter septic system? How much maintenance is involved with these alternative technologies?

In some situations the groundwater is high or there is not enough soil to adequately take care of the wastewater. Therefore, it is necessary to elevate the trenches and add additional soil cover (cap). A capping fill is more costly than a standard system due to the cost of the cap, additional inspections, and labor involved. When space and soil limitations are a problem, some site approvals require a sandfilter. A sandfilter requires a bed of fine, clean sand, pressurized piping, pump tank with floats and alarms and a drainfield. This system is 2-3 times the cost of a standard system due to the design and labor involved. This system requires much more maintenance due to pumps, filters, and piping. We recommend that a maintenance schedule be developed and provided to the County to prevent premature failures.

Can I grow a vegetable garden on top of the drainfield?

Yes, but root crops are not a good idea since there is a potential for contamination. Some drainfields are as shallow as 18 inches, so deep tilling is not recommended.

Can a drainfield be installed in an area of trees?

Yes, but some species of trees are prone to wind damage and uprooting due to shallow roots. This may cause damage to the drainfield. Most tree roots help absorb and evaporate wastewater, but shallow roots may damage distribution or drop boxes.

Will livestock or heavy equipment damage my drainfield?

Yes! Livestock hoofs put large amounts of pressure in small areas causing compaction. Compaction is detrimental to drainfields. Drainfields must have spaces in the soil to hold wastewater and to be able to breathe.