What to do if your leachfield fails?
If your leachfield has failed either on it's own or because of resale testing criteria it is important to properly upgrade the system as this is an expensive undertaking.
Leachfields fail for various reasons, poor design or installation, overuse, inadequate maintenance, rising ground water levels, hydraulic overload. Whatever the reason the cure is usually expensive and involves disrupting the landscaping of the area involved. If your system has failed please check all toilet bowls in the home to see if there is water trickling past the flapper valve or over the overflow tube. This can lead to failure and if there is time, this can be corrected and the leachfield allowed to restore itself. If there are no problems with this then there are several options.
Restoring the leachfield has had limited success in Alaska. Usually if the leachfield is expired, that is, not allowing water to enter the soil, then it is usually too far gone to correct. There are however incidences of restorations by hydrogen peroxide or mechanical "terralift" processes. These services can be located in the yellow pages under "leachfield restoration services". The Terralift website can also be consulted. The author has had very limited success with these solutions and usually recommends the replacement route especially if time is a factor. The municipal health department has certain restrictions requiring retesting on approvals of systems rejuvenated by the Terralift process.
Replacement of the leachfield involves obtaining a permit from the municipality ($300) and an engineer design. If the replacement area was designed originally as part of the initial permit (post 1991), then a test hole may not be required. If prior to 1991 then a test hole will have to be provided and a design drawn up by a registered engineer. This process takes approximately 2-3 weeks plus the installation time. If the system is over 15 years old it is advised to replace the septic tank along with the leachfield as the old steel tanks have probably rusted through.
Unfortunately, many times a leachfield failure or impending failure is discovered at time of home sale. This is because the adequacy test requirement imposed by the municipality is designed to allow for a certain longevity beyond the test period. Engineers are required to prove that the system can absorb 150 gallons per day, per bedroom in the dwelling. This is well in excess of the usual usage of 50 gallons per day, per person. A new system will absorb many times the required amount. Systems expire with age and as the clogging biomat expands. If you are faced with a leachfield replacement you may also have to correct all the prior installation deficiencies and bring the installation up to code. This is all very expensive. One consideration should be to keep the old system "on line" through use of a switching valve that selectively delivers the effluent from the tank to either leachfield. If this is installed, the old leachfield can be allowed to rest and eventually be utilized by simply switching the underground valve. This should be considered a good selling point when you are marketing your home.
Another consideration is installation of the leachfield under winter conditions. If a house sale needs to close and it is winter and -10 outside, the city can issue a conditional permit based on escrowing the necessary money to install the system in the coming summer. Usually a septic system can be installed more effectively and at less expense in the summer work season.