Clog-Free Kitchen and Bath Drains

kitchen sink stainer and strainer basket
This is a typical kitchen sink strainer and strainer basket. Note the slots and holes in both. (C) Copyright 2019 Tim Carter


I was perusing a national news website whose headlines more and more

are reminding me of the traditional sensational tabloids that might have

a story about a lawn being stolen. Being a syndicated newspaper

columnist, I find this transition most interesting.


particular headline caught my eye as it talked about the five things

you should NEVER put down your kitchen drain. I’ve been a master plumber

since age 29 and have had the very good fortune to replace old kitchen

drain lines and unclog newer ones choked with gunk and who-knows-what. I

thought I might discover something I didn’t know.


there were one or two good tips in the article a few of them had me

scratching my head wondering if the author had ever cleaned out a

residential drain line to a kitchen or bathroom sink. I decided to share

with you my experiences with residential drain lines and let you apply

your own common sense. Beware, as a few of the images I’m about to

render might make you squirm just a bit.


think it’s best to describe what the inside of drain pipes look like

when new and after they’ve been in use for years or decades. New cast

iron, copper, galvanized iron, and plastic drain lines all are quite

smooth on the inside of the pipe. You want smooth bore pipe so nothing

gets snagged.


a characteristic of older galvanized iron pipe is that it starts to

develop a rough inner surface that actually starts to get clogged from

small debris that grows hard-water deposits on the inside of the pipe

wall. I’ve cut out galvanized iron drain lines from kitchen and bath

walls and the entire inside of the pipe is choked off with this hard

calcified buildup.

Fortunately, galvanized pipe is rarely used now and it can be found in older homes built between 1900 and the late 1950s. Plastic plumbing drain lines swept the industry by storm in the 1960s and have become the go-to material for almost all residential plumbing drain installations.


want to briefly discuss the size of pipes and what passes through them

with little effort. The drain pipe beneath the toilet in your home is

most likely a 3-inch-diameter pipe. Your body, on a regular basis,

produces solid cylindrical waste that often might be 1 and 1/4-inches in

diameter. You then add paper waste to the toilet bowl, flush it and

magically all of this ends up in a septic tank or your city’s sewage

treatment plant.

Now think about the lowly kitchen or bathroom sink drain pipe. Just

behind the wall of the sink, there’s probably a horizontal

1.5-inch-diameter pipe. Plumbers call this a branch arm. That horizontal

pipe in a kitchen should travel no more than 42 inches where it

connects to a vertical pipe, a stack, that should be at least 2 inches

in diameter. Bathroom sink drains almost always connect to another

1.5-inch-diameter vertical stack instead of a 2-inch one.


the size of solid material that can pass through the branch arms to the

stacks with little effort if enough water is assisting in the process.

In other words, a green pea should have no problems passing through a

kitchen drain pipe.


are some best practices to keep your kitchen and bathroom sink drains

clog-free for decades now that you understand how things pass through



allow grease to go down a drain. It solidifies and will clog drain

pipes. I set aside used paper towels in my kitchen that are quite clean

to sop up liquid grease from cooking pots and pans. These towels are

then thrown in the garbage.


allow flour and egg mixtures into your kitchen sink drains. Dump as

much of this as possible into the garbage. Don’t allow clumps of flour

to enter the drain. Fill the kitchen sink with water halfway and wash

and emulsify the flour coating on the pans and bowls. Pull the sink

stopper and allow this fine slurry to rush down the drain into the main

building drain. As crazy as it sounds, flush a nearby toilet to send the

slurry on its way to the sewer plant or septic tank.


the basket strainer in your kitchen sink strainer and allow it to

capture larger food debris. Dump the debris in the garbage, don’t use

your fingers to push it through the slots in the strainer sending it

down the drain.


you use a disposer in your kitchen, fill your sink with water about

halfway before you turn on the disposer. Remove the disposer drain cover

and turn on the disposer. The giant slug of water will carry the sludge

into the main building drain under your home. All too often homeowners

turn off the water at the sink too early allowing the kitchen drain pipe

to have a liquid slurry laying in the pipes.


a month pour a gallon of boiling water down your kitchen and bathroom

sink. This hot water can dissolve rogue grease that somehow makes it

into the drain and it can dissolve some cosmetics that may be lurking in

a bathroom drain.


you notice a bathroom sink is starting to drain slower and slower, take

a few minutes and remove the stopper. The lever that makes your drain

stopper go up and down does a great job of capturing hair. It takes only

minutes of your time to remove that lever and any debris that’s in the

drain tailpiece where the lever operates. There are quite a few videos

on YouTube showing you how to easily remove and reinstall this simple

part of a bathroom sink.

Once a month pour a bucket of water into your sinks to get as much water as possible flowing down the drain as fast as possible. This is the closest thing you can do as a homeowner to pressure wash the inside of drain lines. Doing this can save you hundreds of dollars that you’d otherwise have to pay a drain-cleaning service should you abuse your drain lines.

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The post Clog-Free Kitchen and Bath Drains appeared first on Ask the Builder.

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