An existing system evaluation is an evaluation done for an existing system due to a proposed changed on your property, whether it be an addition to your home, building a shop, or putting in a swimming pool. Changes made on your property can affect the life of your on-site sewage system, reducing the return on your investment, and the ability to market the property later. 

The original septic tank and drainfield were sized according to the number of bedrooms in the home at the time of installation and the location of the home on the property. Adding more bedrooms increases the number of people that can live in the home. More people living in the home adds to the amount of water and sewage entering your system, putting more of a load on the system, which decreases its life. Adding rooms, additions, garages, shops, etc. to your home/property may change the setback requirements for your system, as well as use up space already set aside as a reserve area for the drainfield.

An inspector will review the records and conduct an on-site evaluation to make sure that the system is still sized correctly for the home, that any additional buildings and/or roads or driveways will stay within the required setbacks, and that the reserve area for the drainfield is still available.

 Part of this process requires that the septic tank be pumped within the past 3-4 years. If you have not pumped your tank within the past 3-4 years you will need to do so. The inspector will want to be at your property while this is being done. If you have had the tank pumped recently, please have the receipt from the pumper available for inspection.

To download an application for the "Existing System Evaluation," click here. Once the application is completed and submitted to our office with the appropriate fee of $275, an inspector will contact you about conducting a site evaluation and any further information they may need. In addition to the application and fee you must submit a plot plan showing us your proposal. This process takes approximately 1-2 weeks.

If you have any additional questions regarding these processes, please give us a call at 509.460.4205.