Best Chemical Drain Cleaners of 2025

For this list, I headed to CNET’s product testing lab in Louisville, Kentucky, to do a thorough distillation with eight of the most commonly used chemical drain cleaners on the market. My primary goal was to determine each product’s efficiency in dissolving different types of clogs, including organic matter, grease, paper products, and pet hair (the same pet hair we use in Our robot vacuum testsin fact). Throughout the experiment, I also observed the pH levels of the cleaning solutions when mixed with water and monitored any temperature changes. Furthermore, I took into account the chemical composition and versatility of each product when comparing them to each other.

Acids versus bases

Before experimenting with these substances, I separated them into acids and bases. As you remember from high school chemistry, acids are compounds that give off a hydrogen ion (H+) when mixed with water and have a pH of less than 7. Bases, on the other hand, are compounds that accept those ions (or hydroxide, OH-). ions) and have a pH higher than 7. Understanding this distinction is crucial, because of two important factors associated with these products: corrosion and causticity.

Corrosion refers to the potential for a chemical to cause rust and deteriorate the materials that make up your piping system. Causticism, on the other hand, relates to how a chemical reacts when it comes into contact with organic materials, specifically breaking down proteins and other organic molecules, which can lead to tissue destruction or chemical burns.

To determine the acidity or basicity of each compound, we measure its pH. In simple terms, the more acidic or basic a compound is, the more corrosive and caustic it is.

Acidic drain cleaners, especially those with high acid concentrations such as sulfuric acid drain cleaners, are more dangerous compared to their basic or alkaline counterparts. In chemistry, the order of addition is important. Typically, you add acid to the water gradually, slowly increasing the acid concentration. Never add water to acid It is known that this reaction generates a large amount of heat and releases dangerous fumesQ. See for yourself in the GIF below (and don’t try this at home).

To ensure safety during experiments, the necessary precautions were taken by wearing personal protective equipment, including safety glasses, gloves, long-sleeved clothing, and a mask. Dissolution testing was performed in a well-ventilated laboratory area to minimize exposure to any hazardous fumes that may be released.

Dissolution test

To start the experiment, I weighed out specific amounts of the blockage material into separate 1000 ml beakers:

• 4 grams of hair
• 20 grams of organic matter (10 grams each of apple peels and carrot peels)
• 40 grams of ghee for spreading
• 14 grams of paper products (7 grams each of toilet paper and paper towels)

Using a graduated cylinder, I measured and added 200ml of each basic drain cleaner and 70ml of each acidic drain cleaner to the respective cups, stirring the mixtures with a glass rod and ensuring thorough mixing without spills. Following the instructions provided with each product, I allowed the solutions to sit for the recommended time, usually between 15 and 30 minutes.

The crucial step in my testing was the inclusion of water, an ingredient often overlooked in similar experiments found online. Chemical drain cleaners are designed to work in the presence of water, facilitating the transfer of the cleaner to the clogs and distributing the solution evenly over their surfaces, enabling the dissolution process. After the specified time had elapsed, I added tap water to each cup containing the cleaning solutions and clog material. For basic drain cleaners (pH > 7.0), I used 500 ml of hot water at 46°C, while for acidic drain cleaners (pH < 7.0), I used 700 ml of cold water at 19°C.

To allow enough time for the chemicals to work, I left the samples to sit overnight and resumed the evaluation the next morning. At this point, the samples turned into a sticky clay mixture.

To continue the experiment, I used a vacuum filtration process using a Buchner funnel connected to a 1000 ml filtration flask equipped with a pump. The contents of each cup were carefully poured into the funnel while the pump was activated. Once most of the chemical drain cleaner was withdrawn from the funnel, I performed a water wash to remove any remaining chemicals from the surface of the debris samples, making sure that only wet solids remained in the Buchner funnel.

Made from chemically resistant borosilicate glass, our Buchner funnel features a perforated plate with 2mm diameter holes, allowing only the smallest particles to pass through. In my testing logic, “If a substance, solid or liquid, can pass through the 2mm holes in the filter, it is less likely to cause a clogged pipe.”

Finally, I separated the samples and subjected them to a fan drying process for a few hours to evaporate any remaining water from the wash. I recorded the final weight of each sample and compared it to its initial weight. The ratio of final weight to initial weight provided us with the dissolution efficiency of each sewer cleaning product.