Chemical drain cleaners include liquid and solid corrosive drain cleaners that are readily available through retail stores, as well as acid drain cleaners that are intended primarily for use by licensed plumbers.
Liquid formulations of corrosive drain cleaners can contain sodium hypochlorite NaOCl (bleach), sodium hydroxide (lye), or potassium hydroxide (caustic potash) in concentrations up to 50 percent. Other corrosive mixtures come as two-part cleaners that are mixed as they are poured in the drain opening. Inside the drain the two solutions react to release a gas, and surfactants trap the gas as dense foam. The intent of this foaming action is to coat the inside of the drain pipe to dislodge more of the substances that form the clog.
Solid formulations of corrosive drain cleaners in the form of sodium hydroxide or potassium hydroxide granules can provide more concentrated effective ingredients. Some patented, solid-formula cleaners add aluminum turnings that react with to the solid hydroxide in water to heat the caustic mixture to a boil.
Acid drain cleaners are intended primarily for use by licensed plumbers because of safety considerations. According to one manufacturer, potential hazards include violent reaction with water and the production of explosive hydrogen vapors upon contact with most metals; chronic (delayed) and acute (immediate) health hazards if inhaled, ingested, or contacted by skin including severe eye and skin burns, inflammation of respiratory membranes, and corrosive burns to all human tissue; permanent visual loss upon contact with eyes; and death if swallowed.
Advantages of chemical drain cleaners include ready availability of some formulations through retailer stores and potential ease of use for removing soft hair and grease clogs that accumulate close to drain openings.
Disadvantages of chemical drain cleaners include a lack of effectiveness for removing clogs far from the drain opening (for example, clogs that occur in toilets or in the main sewer drain), an inability to remove most solid obstructions, and the safety considerations outlined below.
Safety considerations for chemical drain cleaners, the danger arises from their potential to injure eyes, lungs and skin and damage to clothing and household materials such as wood, paint, aluminum and fiberglass. Chemical drain cleaners should be used only according to the manufacturer’s instructions, as other use may cause injury. Strongly corrosive and acid drain cleaners are among the most hazardous household products available to the public.