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Spokane, Washington  Est. May 19, 1883
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Ask the Builder: Keeping drain lines and septic tanks in order

A septic tank about to be pumped. This should be done every two or three years.  (Samuel Corum)
A septic tank about to be pumped. This should be done every two or three years. (Samuel Corum)
By Tim Carter Tribune Content Agency

Q. Howdy, Tim. I discovered on that you’ve been a master plumber for 40 years. I recently moved from a city house on a city sewer to a rural retirement home that has a septic tank. What can you tell me about septic tanks? At my last home, I had clogging issues in my main drain pipe, and the drain-cleaning man said the issue was grease. What are some best practices when it comes to drain lines in any house, and how does one keep them flowing well at all times? – Frank T., Johnston, R.I.

A. Ha! I was in Frank’s shoes 12 years ago when I moved from a city on a municipal sewer to rural New Hampshire with a septic tank. Fortunately, I had a pretty strong background in septic tanks even though during my plumbing career, I installed just a few of them on the outskirts of Cincinnati.

Let’s first talk about the drain lines in any home, be it connected to a city sewer or septic tank. Assuming your drain lines have been installed properly and with the correct amount of slope, water and solid waste should normally flow to the sewer or septic tank with no problem.

The ideal slope of a plumbing drain pipe, in my opinion, is 3/16 inch of fall per foot of run. You might think more slope is better, but if you have too much slope, the liquids can outrun the solids as they move down the drain lines. You don’t want this to happen as solid material sitting in a drain pipe can start to build a clog.

Talk to any municipal sewer worker or septic-tank pumpers, and they’ll tell you grease and newer flushable wipes are big nightmares. You would do really well to sop up all grease from your cooking pots and pans with used paper towels. Put these grease-soaked towels in your garbage. This means even wiping grease-covered plates with used paper towels before washing them. You want to minimize all grease from entering your plumbing drains.

You can use flushable wipes if you want, but don’t flush them. Put them in a sanitary garbage can in your bathroom. (Watch my video on flushable wipes at to see why you should never, ever flush these fabrics.)

You can go online and buy products that contain active bacteria that will start to eat grease that might be coating the insides of your pipes. It’s a great product that will also prevent septic tank leach fields from getting clogged with grease.

Here are a few things I do at my own home to keep my drain lines flowing. I pour about 15 gallons of very hot water down my kitchen sink about once a month. Hot water does a pretty good job of dissolving grease, and this is an alternative to buying the bacteria product that eats grease.

Each week, I pour 10 gallons of water as fast as possible into the highest toilet in my house. As I learned in high school physics, this water creates a vigorous flash flood within the pipes and especially the horizontal building drain pipe below my basement floor.

Not to be gross, but the best analogy I can give is imagine blowing your nose. You get just about everything out, and the pipes are wide open.

Septic tanks are magical boxes as long as you use them correctly. In an ideal situation, the only thing that would enter a septic tank is what comes out of your body and any tiny food scraps that might make it past a kitchen sink strainer. That’s all you should ever put in a septic system.

Mother Nature then takes over inside the tank. Natural bacteria start to eat the waste. When a tank is operating as it should, each time you flush a toilet and 1.6 gallons of water enters the tank, the same amount of partially treated wastewater leaves the tank headed to the leach field.

A leach field is almost always a network of pipes where the wastewater is distributed to a very well-drained soil that’s very sandy. The water seeps out of holes in the pipes and enters the sandy soil. Here other bacteria and oxygen work hand-in-hand to purify the wastewater.

Understand that the water that leaves the leach field becomes ground water. Once purified by the good bacteria and oxygen in the soil, it can almost be as pure as rainwater. I know this sounds hard to believe, but understand that in many rural areas, a leach field from one neighbor is on higher ground than the neighbor below. The water naturally flows downhill on its way to the ocean.

You never want to put chlorine bleach, or products containing it, into a septic tank. This bleach is so strong, it can kill the bacteria that eats the waste. Any other chemicals are bad, too. The same goes for paint. Never clean paint brushes inside a house and allow that water to enter the septic system.

It’s very important to have the septic tank pumped every two or three years. Know where the manhole is that gives the technician access to the tank. As crazy as this sounds, my neighbor’s manhole is buried about 4 feet under his driveway. I saw his house being built, and the builder and plumber never installed risers to get the manhole closer to the surface. That’s a giant mistake!

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