Septic Tank Pumping Tips

DEAR TIM: I've heard all kinds of advice about septic tank pumping and am more than flummoxed. Some of my neighbors have never done it and others say it needs to be done frequently. When should you pump a septic tank and why? What happens if you forget or don't do it when it needs to be done? The cost for septic tank pumping seems really high and I'm wondering if it's worth it. Carrie S. Hillsboro, OH

DEAR CARRIE: You're going to hate me, but there is no definitive answer as to the exact intervals of when a septic tank needs to be cleaned and pumped. Many professionals who do this work will tell you that it should be done every three years, but there are septic systems that probably should be pumped annually.

This is the access hole cover for a septic tank. Don't even think of removing it unless you're a professional septic tank cleaner. PHOTO CREDIT: Tim Carter

Let's talk first about why septic systems need to be pumped. Waste water from your home contains solids. Some of these solids do break down in the tank and are devoured by bacteria in the tank. But think about it. When you wash dirty clothes, what happens to the small rock particles and dirt? They settle to the bottom of the tank.

Other solids that can't be digested and broken down start to accumulate on the bottom of the tank reducing the amount of water in the chambers of the tank. Furthermore, there's a layer of scum where floating material like grease and lightweight solids start to accumulate. These also, over time, reduce the amount of water in the tank. You need water in the tank to fuel the breakdown of the solids.

If you don't get sufficient breakdown of the solids in the tank, the small particles pass through the tank and are delivered to your leach field. The leach field is a critical part of the waste-water treatment system of a standard septic system. This field consists of perforated interconnected pipes into which the effluent from the septic system flows. Usually the pipes are surrounded by sand or very loamy soil.

As the nearly clear effluent from the septic system passes through the sand and soil, the remaining pathogens are removed and safe water remains. A septic system that's in good working order does not pollute the ground water nor the surrounding area.

However, if solids are transported from the tank to the leach field because they are not broken down in the septic tank, the leach field, over time, will fail. If this happens, you will create a serious pollution hazard, and you could create health issues for your family and surrounding families.

Regular pumping of a septic tank ensures you'll not ruin your leach field. Replacing a leach field is an expensive proposition that costs thousands of dollars. The price to pump a septic tank is usually just several hundred dollars. It's well worth the price.

The reason no one can give you a definitive time frame of when a septic tank should be pumped is really quite easy. It's all a function of how large the septic tank is and how many people are discharging waste into the tank each day.

Most towns, cities and counties that regulate the installation of septic systems require you to get a professional septic design or plan produced before the system is installed. The designer takes into consideration the size, or number of bedrooms, and the total occupancy of the house.

Using this data, they can size the actual tank. The trouble is, you may have purchased a home and have no idea if the current tank is sized properly for the number of people living in the home. If this is the case, I urge you to get a real professional out to your home that has years of experience with septic tanks. Frequently they can tell the size of the tank after it's pumped. Once they know that, they can tell you how often it needs to be cleaned and pumped.

I was very lucky when I bought my recent home. The previous homeowner had the original septic tank permit as well as several copies of the plan drawn by the septic designer.

The plan clearly shows the exact tank, the size and capacity in gallons of each chamber of the tank and even the type and model number of the pump I need in my system. Unfortunately, my leach field is higher in elevation than my tank, so the effluent from the tank must be pumped about 30 feet uphill to the leach field.

These plans are like gold. If you have them, keep them in a safe place. The permit is also very valuable. Some states now require the seller of the home prove the septic system was authorized when it was installed. Without the original permit in hand, you may spend hundreds or thousands of dollars proving your system was installed correctly.

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