Effects of Bleach on a Septic System

Because the key to a functioning septic system is the bacteria that lives in your septic tank, an overload of harsh chemicals, such as bleach, could potentially kill off the bacteria in your tank and cause problems in your overall system. The bacteria in the tank provides an anaerobic (meaning that oxygen is not required) breakdown of solids in the tank.     

According to a recent research study (Gross), bacteria in a septic tank can be killed if there is an overabundance of toxic substances. Research showed that 1.85 gallons of liquid bleach, 5 gallons of a liquid cleaner or 11.3g of a drain cleaner in a standard 1,000-gallon septic tank can cause a bacteria “die-off.” The study noted other substances that were harmful to the tank bacteria including anti-bacterial soaps and cleaners.

A short-term use of household cleaners should not cause a permanent die-off of septic tank bacteria, but long-term use resulting in a bacteria die-off could result in greases, oils and solids being pushed out of the tank into the drain field. If these elements get into the drain field, it can result in blockages and ultimately a failed drain field system. Symptoms of a failed drain field include slow drainage and flushing of drains and toilets in the house, as well as standing water on the grass or soil over the drain field. A completely blocked drain field will cause a backup into the house.

Discontinuing the use of harsh cleaners and chemicals is the first step. Over time, bacteria will naturally begin to reproduce in the tank, and a live colony should become established. Although many over-the-counter additives are sold, these substances can actually lead to septic tank problems as the solids and “scum layer” in the tank are often broken down and then flushed into the drainage system, causing blockages.

GROWING VEGETABLES OVER A LEACHING BED IS NOT RECOMMENDED

Growing vegetables over a drainfield is not recommended.  There are several reasons why:

• septic systems receive household wastes from toilets, sinks, showers, dishwashers, washing machines and other indoor water uses
• the leaching bed part of the septic system most commonly consits of a series of parallel perforated pipes in the grund about 12 to 18 inces deep.  The pipes are set in gravel trences that allow treated effluent from the septic tank to seep into the ground.
• the leaching bed is the most expensive and the most potentially problematic part of your entire septic system
• vegetables need watering and excess water in the soil would reduce the leaching bed's ability to treat the wastewater
• the water does not go straight down, it diffuses out first
• during heavy rain, run-off, or snow melt water can actually go up, and rise in the soil
• while nutrietns may be beneficial for the plants to a degree, excess Nitrogen also poses problems for plants and all the bacteria in the soil may not be quite so beneficial
• the deep roots of some vegetable may damage the drainfield pipes
• bed preparation, such as roto-tilling or deep digging can also damage the drainfield pipes
• the soil over the leaching bed tends to settle over time and that allows roots access to it causign plugging of the field as weall as contamination of any foods grown there
• the leaching be perforated pipes are only buried 12-18 inches under the ground so digging or roto-tilling in your garden could damage the pipes