Waiting too long before scheduling septic tank pumping could leave it in an unsalvageable condition, leading to damage of the tank itself and saturation of the drainfield. Since the septic system is in operation all year round, it would be better to err on the side of caution and have it inspected annually for problems such as clogging, damaged piping or a leak in the tank, instead of waiting for a problem to manifest.

Septic tank pumping is a vital part of ensuring the system runs strongly. However, there are certain situations that could make such pumping unproductive. Here is a look at two such scenarios and why you should postpone pumping in such cases:

Low sludge levels

Your septic system works by separating waste from your home into sludge - which comprise of solid waste - and a scum layer of grease. The scum floats to the top, and is separated from the sludge by a layer of clear water called effluent. This effluent is treated by bacteria in the tank, and later released into your drainfield for absorption. This way, the septic tank can process waste from the house for extended periods without filling up.

If the sludge level is very low, and the scum layer of minimal thickness, there is no danger of the tank filling up or clogging, so pumping it out would be detrimental and unnecessary. The danger in pumping the tank out at such a stage is that the effluent level would be reduced, and there would be no chance for new waste to separate into scum and sludge.

This would rob the system of its ability to process your wastewater, leading to untreated sewage finding its way into your absorption field, which would cause soil contamination and saturation.

Letting an expert inspect the scum and sludge level using a probe could help reveal whether any pumping would be needed, and how the septic tank is separating solid and liquid waste.

Septic tank inspection and testing

Regular tank inspection and testing is necessary to reveal problems such as a failing system or damaged tank. Experts usually run water and red dye into the system to check for evidence of clogging or effluent breakout on the yard surface.

Having your septic tank pumped shortly before such testing would hide an imminent or already failed system, such as one with backup problems or dangerous site conditions like a collapsing tank or an old cesspool. An empty septic tank is misleading, as it disrupts the portion of a septic loading and dye test, hiding existing problems.