Categories: MaintanencePlumbing

Septic System Maintenance

Here in New Hampshire septic systems are the primary way of treating domestic waste water. In rural areas that don’t have municipal sewer systems a septic system is the best way to treat waste water. I designed our new septic system for the new home we just built and my wife often asks me questions about what she can and can’t pour down the drains. So I figured I’d write some posts on maintaining your septic system so that it gives you many years of good service.

To help you better understand the proper way to maintain a septic system it’s important to understand the basic way they operate. For those of you wishing to know more detailed information about how septic systems work I’ll be doing another post on that in the near future. Most septic systems work basically the same way. Typically the waste is treated in a two step process.

The first step in the septic treatment process is to dump all of the sewage into a septic tank. Once the tank fills with sewage it breaks down into three basic levels; the bottom level is the sludge level, the middle layer is the raw waste water and the top level is the scum layer. The tank is designed to hold the waste water until the solids settle to the bottom sludge layer. The solids are partially decomposed by bacteria. The grease and light particles float to the top layer of scum. The tanks purpose is to separate the scum and solids and keep them in the tank. Once that happens the waste water drains out of the tank to the second step in the treatment process.

The second step in the treatment process is the drain field. There are many different types of drain field designs but they all work pretty much the same way. The waste water slowly drains into the drain field through solid pipes. Once in the drain field the water enters some type of slotted pipes. The pipes may have some type of fabric around them and either a stone bed or sand bed depending on the design. As the water slowly seeps into the soil dissolved wastes and bacteria in the water are trapped or adsorbed to soil particles or decomposed by microorganisms. This process removes disease-causing organisms, organic matter, and most nutrients (except nitrogen and some salts). The remaining clean water just drains into the soil layer.

Obviously this is a simple explanation of a complex system but understanding that this process is controlled by bacteria is the key point. Knowing that means you must be VERY careful what you put down your drains as far as chemicals that might kill off that bacteria and therefore stop the septic process. The following steps will help you maintain your septic system:

Do not use commercial septic tank additives. Although they will not necessarily harm your system, they are not necessary and do not eliminate the need to pump your tank.
Know the location of your septic tank and leaching area.
Inspect your tank yearly and have the tank pumped as needed and at least every three years.
Do not flush bulky items such as throw-away diapers or sanitary pads into your system.
Do not flush toxic materials such as paint thinner, pesticides, or chlorine into your system as they may kill the bacteria in the tank. These bacteria are essential to a properly operating septic system.
Repair leaking fixtures promptly.
Be conservative with your water use and use water-reducing fixtures wherever possible.
Keep deep-rooted trees and shrubs from growing on your leaching area.
Keep heavy vehicles from driving or parking on your leaching area.

In future posts I want to go into more detail about how septic designs work and also look at safe products you can use that will keep your septic system working properly for many years.

Todd Fratzel

I'm full time builder for a large construction company in New Hampshire. I run their design-build division that specializes in custom homes, commercial design-build projects and sub-divisions. I'm also a licensed civil and structural engineer with extensive experience in civil and structural design and home construction. My hope is that I can share my experience in the home construction, home improvement and home renovation profession with other builders and home owners. I'm also the Editor-in-Chief and Founder of Tool Box Buzz. Please feel free to contact me if you have any questions, suggestions or you'd like to inquire about advertising on this site.

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View Comments

Mike@RuralRenovation says:
June 5, 2008 at 1:35 pm
Hi Todd, Thanks for stopping by...
Once we find our septic system (yes find) I'm assuming it is going to need a major overhaul. Thanks for the great information. I'm sure I'll be keeping up with your site as I go though my renovation.