How Often to Pump Septic Tank for a Family of Four?

Answering the question "how often to pump a septic tank" is like figuring out how often to change your oil without an odometer reading. It depends, right? The oil change question is easier to imagine because most of us know it will depend on how much the car is used, how much the engine is running, how big the engine is, how the car is driven, what type of oil is used, what type of car it is... You get the picture. Answering the question for a septic tank is similar:

• How big is the tank?
• How many people are in the household?
• What type of chemicals are going down the drain and how often?
• What are the water usage habits in the household?

Bobvila.com states:

Generally, a septic tank should be pumped every 3 to 5 years. 

Maintaining a septic tank system isn’t all that expensive, but it’s definitely more costly to dig up and repair or replace a system that has failed due to neglect. Some septic systems may need to be pumped once a year depending on the tank size, number of people in the household, and amount of wastewater produced. Other systems may be able to wait 5 years between each septic pumping. On average, it’s recommended that you call in a professional every 3 to 5 years to maintain the life of your septic system. The frequency with which the tank needs to be cleaned depends on the level of waste in the tank and not a specific time frame.

At Double Flush Septic Services many of our customers choose maintenance plans in order to take the guess work out of their septic system maintenance. When our clients are on a septic maintenance plan we are familiar with their septic system and septic cleaning (or septic pumping) needs.  All the septic tank pumping is done preventively to optimize the lifespan of the septic system and monitor the household's use for any needed adjustments.

To keep the answer simple it depends on the amount of solids that are in the tank. Septic tanks should be clean when they are at about 20 to 25% solids. This means, in a conventional 1,000 gallon septic tank, it holds five feet of water.

Sludge Judge Can Tell Us When to Pump Your Septic Tank

We use a tool called the Sludge Judge to take a core sample of the cross section of the septic tank.  We dip it in, and when we pull it out we see how much solid is on top (scum layer in image) how much clear water is in the middle and how much sludge is in the bottom. We add up the amount of solids, let's say there's six inches of top scum and six inches of bottom sludge, that's a foot of solids. In this case one foot of a five foot capacity septic tank is 20% solids, so the tank is ready for a cleaning.