Chemical Drain Cleaners: Are They Any Better?

In our previous post on best drain cleaner and best drain cleaner for grease, we covered the best tools to clear your drains from any type of clogs. I kept pointing that mechanical drain cleaners are your best bet against all types of clogs. You might be wondering why I selected mechanical drain cleaners, rather than liquid cleaners that are always advertised by other blogs. Well, this article is to clarify my position on why chemical drain cleaners are not the best.

Many homes, especially the old homes use cast iron or galvanized drain lines. Overtime, the drain may become clogged, leading to slow drain in branch line fixtures such as laundry, shower, tubs and sink discharge lines. The overall result is that water movement down the drain slows or ceases, as the clogs are blocking, both the flow of water and gas down the drain. When this occurs, most home owners will grab a bottle of chemical drain cleaner and flash it down the slow drain line. However, most chemical drain cleaners are very toxic and corrosive. To understand the consequences of using chemical drain cleaners, it is important to first examine how they work

How do they Work?

Whether they are in powder, gel or liquid form, chemical drain cleaners contain strong corrosive chemicals. Generally, the chemicals work by either giving or taking electrons from the clogs. A chemical process which results in the dissolution of the clog, while at the same time generating heat. There are two types of chemical drain cleaners.

Alkaline Drain Cleaners

The primary chemical in alkaline cleaners is either potassium hydroxide or sodium hydroxide. Potassium hydroxide is commonly referred to as caustic potash, while sodium hydroxide is known as lye.  In addition to these two chemicals, the drain cleaners also contain aluminum particles and other additives that are not disclosed as they are the trade secrets of the manufacturer. These chemicals react in a heat forming process, whereby the chemicals donate their electrons to the substance that makes up the clog. In most cases, the substance is a natural substance such ass oils, grease, fat and hair. The hydroxide ions in the drain cleaner attack the clog through a process known as saponification, producing a soapy dense liquid (hence the word saponification or formation of soap).

Solid formulations mainly contain lye, a compound that is hygroscopic (tends to absorb moisture from air). When placed in water, it absorbs the moisture creating another clog, which reduces their effectiveness, unless placed directly over the clog. In contrast, liquid formulations contain lye or caustic potash, and also sodium hypochlorite. When placed into the drain, the produce surfactants, heat and gas which corrode the clog, therefore dislodging them. Liquid drain cleaners are denser than water, which allows them to sink to the clog and dislodge it.

Acid Drain Cleaners

These are primarily made of sulfuric or hydrochloric acid at very high concentrations. They remove clogs through a process known as acid hydrolysis. In hydrolysis, a large molecule is broken down to simpler and smaller molecules through the addition of water molecule. When such a process occurs in the presence of an acid, then the process is known as acid hydrolysis. In the later process, the acid provides the hydrogen ions to the larger molecule for the purposes of intake of water molecules. This is the general process through which acids clear out clogs, by donating hydrogen ions to the clog, which leads to their breakdown. Most acid based chemical drain cleaners are only sold to plumbers and other specialists.

Oxidizing Drain Cleaners

Most of these drain cleaners contain peroxides and nitrates. They oxidize the clog by taking electrons from the clog, thereby oxidizing them. Oxidizing drain cleaners are heavier than water and will sink to the clog when put into a standing pool of water. The reaction between the oxidizer and the clog will produce gas and heat which help in clearing the clog.

We do not recommend chemical drain cleaners for the following reasons:

They are hazardous

Chemical Drain Cleaners are highly ToxicStatistics by the American Association of Poison Control Centers indicates that at least 2 million instances of poisoning and injuries from alkaline drain cleaners are reported each year. These numbers do not incorporate the number of people who injured by drain cleaners. The majority of these cases involve adults. Of the 2 million exposures, around 100,000 resulted either in death or major injuries. This means that the potential of fatalities if you properly mishandle these chemicals is very high.

Chemical drain cleaners are a danger to personal health and the environment as a whole. Mishandling of the chemicals can lead to injuries to the skin, lungs and eyes.

Sodium hydroxide, a key ingredient of chemical based cleaners is toxic to oral and dermal routes (mouth and skin).  Simply, it can burn your mouth, skin or eyes if not handled properly. Ingestion of this chemical is mostly accidental and the most important victims are children. Therefore, keeping such chemicals in your home can harm your children. On the other hand, if the chemical accidental enters the eyes, then it will liquefy the eyes if medical help is not sought immediately. Lye and caustic potash cause the most damage if one is unable to seek help. It is important to also note that a drain cleaner containing just 5% of these chemicals will cause severe burns. So, when settling for chemical cleaners, be aware that they can cause bodily injuries that may even require hospitalization, whenever they are mishandled.

They are a threat to the Environment

When you use a chemical drain cleaner, the contents that do not react with the clog, goes down the drain and into the environment. Although most of the chemicals are broken down into harmless compounds, they skill cause a lot of problems to the environment. First most chemical cleaners are packaged in plastic bottles. These create environmental problems by contributing to the large mounds of waste that require either recycling, incineration or dumped into landfills. Most cleaner bottles are made from high density polyethylene (HDPE), which can be recycled, but is not mostly recycled due to poor policies. Others are made from PVC and vinyl chloride. The latter is a known carcinogen (causes cancer). Most recycling companies do not accept both vinyl chloride and PVC for recycling.

They Will destroy your Plumbing

Most chemical drain cleaners produce heat when they react with clogs. If for example you use a hydrochloric or sulfuric acid based drain cleaner, then there is a high probability that the drain pipe will explode, as the two ingredients react violently with water. Furthermore, lye, caustic potash and these two acids erode older pipes such as iron pipes and PVC. Overtime, the pipes become thinner and burst. In the short term, you will never notice that the chemicals are eroding your pipes. You will only realize when the drain pipe bursts. Furthermore, these chemicals can also chew you sink, or any other finishes in your bathroom or kitchen, either discoloring them or damaging them. If you do not identify the damage in time and they start leaking, you can be sure that your house will suffer from mold and water damage.

They are not Highly Effective

Chemical drain cleaners will only soften the clog. When the water starts moving, the remaining drain cleaner is washed into the sewer where it breaks down. Therefore, the problem will likely to occur within a short time. For permanent solutions to clogged drains, you can read our advice on best drain cleaners for grease and best drain cleaners.


It is clear that chemical drain cleaners are not the best option, owing to their hazardous characteristics. While picking up that bottle from your storage shelf is convenient, think about the potential problems that arise when you use its contents. We have reviewed some of the best drain cleaners around, that are not only reusable, but also safe to you and the environment. All you need is to get your hands dirty.