Dear Barry: We just moved from the big city to the country. So for the first time ever, we have a septic system and have to think about what goes down the drain. The contractor who inspected the septic tank advised us to flush an additive down the toilet once a month to maintain the bacteria level in the tank. Our new next-door neighbor says he’s never used the stuff and insists that it’s a waste of money. What’s your advice for the care and maintenance of a septic system? Jeffrey
Dear Jeffrey: Bacterial additives are often advised by septic contractors, but the need for this is debatable because micro-organisms are added to the tank every time solid waste is flushed down the toilet. In fact, more attention should be given to things that should not be flushed than things that should be.
Several studies have been conducted to determine the effectiveness of septic additives, including one that was published in the Journal of Environmental Health in 2008 and another that was conducted at the University of Ottawa in 2012. In each case, the additives did not significantly increase the bacterial level in the septic systems that were tested. Many septic contractors will no doubt disagree with these findings.
Rather than adding bacteria to your septic system, it is important to protect the bacterial environment that is already present. Here are some do’s and don’ts for maintaining the effectiveness of your septic system:
1) Avoid putting insoluble solids such as grease, fats, and oils down the drain because these can clog the leach lines that convey water from the septic tank into the ground. Keep this in mind when washing pots and pans.
2) Don’t put chemicals such as paint, paint thinner, bleach, etc. down the drain. People sometimes clean their paint brushes in sinks and toilets. This is definitely a no-no.
3) Minimize the use of your garbage disposal to avoid the accumulation of undigested organic solids in the tank. These can take a long time to decompose.
4) Do not let the salt brine from a water softener drain into your septic system. Instead, the discharge pipe from the softener should terminate in a ground sump or leach field designated for this purpose.
5) Minimize the amount of extra water that goes into the septic system. For example, rain gutters from the roof and yard drains should not drain to the septic tank or the leach field.
6) Do not park vehicles on ground surfaces above the leach field, as this can compact the subsurface absorption system.
7) Have your tank pumped and inspected in a timely manner, usually about every five years.
Laundry drains are often diverted to a ground sump or garden area to prevent detergents and other laundry additives from damaging the bacteria in the septic tank. The need for this precaution is often unwarranted because newer types of detergents and bleaches do not adversely affect the microbial environment in a septic tank when used in moderation. I can attest that my own septic system has consumed detergents for the past 10 years with no apparent ill-affects. This particular advice, however, is likely to draw active debate from some septic contractors.