Ask The Experts
I am interested in buying a rural property that has a septic system. The house has been vacant for a long time, and I understand that it's hard to test a system that isn't being used. What can I do to protect myself in case the septic system isn't any good?
Septic systems are designed to take the waste water from our homes, treat the water, and disperse it into the ground. The systems are expensive and normally have a limited life of 20-25 years. Septic systems typically suffer from neglect. They're generally out of sight and out of mind, and don't reach our consciousness until something goes very obviously wrong. Unfortunately, by the time we know that something is not right, we often have a big expense on our hands.
It is true that testing the septic system on a vacant house is nowhere near as reliable as testing an occupied house. The basic concept of dye testing, (which is the most common method of assessing the condition of a septic system for real estate sales), is to run water into the system from a sink or tub, along with dye, to simulate the maximum normal usage that the septic system is likely to experience. Typical maximum use might be during morning “rush hour”, including a few showers and a load of laundry as your family heads out the door. This is simulated in a test by running 50 gallons of water per bedroom, and inspecting to see if the system can handle the volume, or if the effluent backs up into the house or shows up in the yard. If the house has been vacant, water levels in the system may be well below normal, and the test may only be bringing the levels up to low usage levels, not the maximum, and therefore not really taking the measure of the system.
It still may be wise to do the test. If the system fails anyway, you will be aware of the failure before buying the house. But if it passes, you won't be sure of the test's validity. Alternatives include having someone simulate normal usage by running water into the system for several days before the test. You may also be able to arrange for a portion of the money you are paying for the property to be held in escrow at the time of closing to cover the cost of a new or repaired septic system. You would then have the system professionally tested after you occupy the house, and if the test results indicate that the system has failed, use that money for repair costs. In any case, it is smart to also have the tank pumped and inspected after a dye test is performed, for greater assurance. It is also wise to check with local authorities to determine if the system was installed in compliance with state sanitary codes.
I have a septic system at my house and would like to install a garbage disposal. I see that there is a disposal specially designed for septic systems. Have you had any experience with this product?
Kitchen garbage disposal units can add a significant amount of biological waste material to an on-site septic system and are therefore recommended against by most authorities. In our experience disposals are allowed in new construction but the design parameters for newly installed septic systems need to be increased to accommodate the added load from the disposal unit. Septic systems operate by anaerobic digestion of waste products in the septic tank. Solids settle to the bottom, greases form a layer on the top, and relatively clear liquid passes on into the soil, (hopefully out of sight and out of mind), for final treatment by soil bacteria before reintroduction to the water table. In our area, the clear effluent is usually introduced into the soil in a dispersal system consisting of a leach field or a sand mound.
The garbage disposal you refer to adds enzymes to the septic system each time it is used. This is supposed to accelerate digestion, compensating for the added load on the septic system. The problem is that adding enzymes, or any other additive for that matter, has not been proven to increase digestion. In fact, yeast type additives may even shorten system life by agitating the effluent in the tank, causing more solid matter to flow into the leach field where it can result in clogging and failure of the system. Most authorities recommend against putting any additives into the septic system. If you have a relatively new, well-designed septic system, and do not anticipate heavy usage, based on the number of occupants in your house, you may be able to get away with adding a garbage disposal without overstressing your septic system. However, from our experience, there is no particular advantage in these new disposals that add enzymes into the system along with the food waste.
Remember that food waste adds to the total solids and will likely shorten the time between necessary septic tank pump outs. Tanks should normally be pumped out every two to five years depending on usage. Plan on more frequent pumping, if you install a garbage disposal.