Lye is often used as a drain cleaner. It converts grease into soap which is easier to flush.

It is also heavily used to clean food containers, wash bowls, and room vessels as it possesses bacteria-killing properties.

Just from this statement, you already know that lye is risky to septic systems.

It can kill bacteria used to process waste.

What is lye?

The simplest definition of lye is an alkali or a base known for its caustic nature. As far as cleaning goes, this is a strong alkali metal hydroxide that dissolves in water to produce caustic solutions.

When you see lye on your grocery store shelves, know that it refers to sodium hydroxide or caustic soda (NaOH).

 It is one of the main ingredients in the soap-making process.

Potassium hydroxide or KOH is also a common lye used to make soap and other products.

Traditionally, lye was made from leaching wood ashes.

Now, it is manufactured through a membrane cell chloralkali process.

It is available in liquid forms, crystals, or flakes.

Too Much Lye Can Cause The Death Of Septic Tank Bacteria

Caustic soda is more or less like hydrochloric acid or sulfuric acid as far as corrosion is concerned.

While one is an acid and another one a base, both are powerful enough to kill bacteria present in septic systems (or anywhere else for that matter).

However, its safety really depends on the concentration of the lye and how often it makes its way into your septic tank.

For example, if you have a 1000-gallon septic tank and use about 0.3 gallons of 15% caustic soda, you may not experience much of a difference in the tank bacteria.

This is because, from the get-go, the lye is relatively dilute. When you add it to your massive tank, it gets further diluted by the high volume of sewage in it. Eventually, the effect on your bacteria colony will be minimal if any.

The opposite is also true. If you have a much smaller tank and use a higher lye concentration, expect it to kill a large amount of your bacteria. This is made worse if you use the lye on a daily basis or a few times a week.

Safety Tips When Using Lye For Septic Systems

Now that you know the risks lye poses on your septic tank, caution is a must when using it.

 Obviously, the safest thing would be to do away with lye altogether.

There are thousands of products that can replace the chemical – both homemade and commercial options. Most work without irritating your skin and wreaking havoc on your septic tank.

If you have to use lye (for whatever reason), go for the lowest concentration possible.

Typically, commercial soap formulations use 25%-40% lye.

 The lower range has more water and is thus less risky than the higher range.

The alkali is also available in a 50% concentration and this is often considered to be too strong.

Never use it as an independent cleaner or use it for a certain formulation. Not only will it burn you but it will certainly kill most of the bacteria in your septic tank.

Finally, even with the mildest lye, reduce the number of times you use it if you have a septic system.

Once in a while will do little or no harm to it. Pick up safety-safe cleaning products for your daily or weekly cleaning chores.