There can be a lot of conflicting information on how frequently you should pump out your septic tank. If you've experienced the pain, frustration, and cost of a backed-up septic system, you know that getting it wrong can have unpleasant consequences. On the other hand, getting residential septic services too frequently is a lot like pumping your hard-earned money directly into your drain field.
Ultimately, it's always better to be safe rather than sorry when it comes to septic tank pumping. Spending a small amount of extra money on excessive pumping is better than allowing sewage to back up into your home, after all. You can also take a more scientific approach, however. Keep reading to learn how you can measure the best pumping schedule for your home.
Understanding Sewage Retention Time
The key to knowing when your septic tank is "full" is to understand how long your effluent remains in the tank. This period is known as the retention time. Under normal circumstances, effluent stays in your tank for a few days, which provides time for grease and solids to fall out. Note that the exact time varies based on tank size and other elements of your system's design.
When the solids and grease levels in your tank are too high, they displace effluent from the tank. Ultimately, this reduces the retention time below the required limit. Since effluent is now being pushed out of the tank too quickly, solid waste and grease usually end up in the drain field. Over time, this clogs your system and can ruin your drain field.
Measuring Your Tank's Scum and Solids Content
There's typically no easy way to measure the effluent retention time of a tank while it's in use, but the thickness of the scum layer (on top of the water) and solids layer (at the bottom of the tank) serve as useful proxies. A septic system cleaning professional can inspect these levels for you. The best time to measure your levels is before you clean the tank.
By measuring these two layers, you can determine the percentage of your tank displaced by the combined volume of scum and solid waste. From this value, you can decide if you are tanking your pump too frequently or not often enough. In general, you should pump your tank before the sludge layer displaces a third or more of the tank's volume.
The Advantages of Measurement
Measuring tank levels during a septic cleaning can help you decide on a more efficient pumping schedule, ultimately saving you money while keeping your system working well. If in doubt, however, remember that the consequences of deferring a septic tank cleaning can be dire. Always err on the side of caution when choosing how frequently to pump your tank.