When sewage treatment systems fail, it is often difficult to determine where the problem lies and how to overcome it. This learning task will cover common issues, their indicators, and offer acceptable solutions.

With routine maintenance, most septic systems will be trouble free. However, when problems arise, they originate in areas of a system that can’t be seen or easily accessed. The following are not a complete list of issues that could be encountered — they are the most common ones.

Slow or Stopped Drainage

Fixtures that drain slowly or not at all are an indicator that the piping downstream is partially or fully blocked. Check first to see that the problem is not in the house piping or the building drain. If not, assume that the tank is not draining as it should. Firstly, check the observation ports in the field trenches, as these should be easy to find and access. See if the field is saturated. If so, this could be the result of a high seasonal water table, unusually high recent rainfall, or a plugged field due to excessive biomat formation. Remedies to consider would be to firstly reduce the house water use as much as possible, to give the system time to recover. In the case of excessive biomat, consider the use of biological additives to help break down the biomat and restore the permeability of the soil. Alternatively, the field may have to be abandoned and replaced, and this should be considered a last resort. If the field is dry after checking the observation port, check the liquid level in the tank. If sludge buildup is too high, it can plug the outlet pipe or the inlet to the pump if using a dosed system. In that case, have the tank pumped and clean any filters at the outlet. If a pumped system is in use, check that the pump and all float switches and sensors are operating properly, and replace any that are found to be faulty.

“Ponding” over the Dispersal Field

Soggy, wet ground or puddles forming on the ground above a dispersal field is evidence that there is either a leak or break in the piping somewhere between the house and the field piping, or that the soil is not absorbing the effluent fast enough.

In the first case, check the piping between the house and the tank, the tank and distribution box (if used), and the distribution box and field piping to ensure that there is flow at these points, and if not, work back upstream to determine where the break in the piping may be. Once the leak location is identified, the ground will have to be excavated and the pipe break repaired.

For the latter case, once the pores in the infiltrative surface within the field trenches become plugged by biomat, effluent will find its way upward, rather than downward, through the soil. Again, the use of biological additives may correct the situation, but this will not happen immediately. Reduce water use in the building to allow sufficient time to see if the additive(s) are working. Again, a more immediate albeit costly fix would be to replace the dispersal field piping.

Contaminated Drinking or Surface Water

If the system has otherwise been operating properly up to this point, it can be assumed that untreated sewage is making its way to these water bodies. Septic tanks can develop cracks that cause raw effluent to leak into the surrounding soil. This is a serious issue that must be corrected immediately. An AP or professional would be consulted in any case, who would determine whether it can be repaired or must be replaced.

Proximity to a neighbouring septic system or source of contamination that isn’t on the owner’s property should also be investigated, especially if there has been recent groundwork done there.

Overall Troubleshooting

In every case, especially when the house drains into a septic system, use as little water as possible. Repair any drips from faucets and replace old wasteful fixtures with ones that are of the low or ultra-low consumption variety. Avoid discharging the waste or rinse water from softeners, iron filters and such into the system. This adds unnecessary volume and may introduce harmful chemicals. In all cases, whenever problems are encountered, always try the simplest, most cost-effective remedies first.