The Best Acids for Cleaning Plumbing Pipes

As a professional plumber, you've likely encountered stubborn clogs that resist your standard drain-clearing tools. When this happens, turning to chemical solutions can be the most effective way to break through the blockage. If the clog you're dealing with is caused by organic matter like grease, hair, dirt, or soap scum, acid-based chemical cleaners will break down these materials to restore the flow. Acid drain cleaners offer a powerful and fast-acting method to clear drains, but they also come with risks. Proper knowledge and caution are essential to avoid chemical burns or inhaling harmful fumes. 

Check everyone in your team is aware of workplace risks with our free H&S checklist! 

Low on time? Skip ahead! 

1. Sulfuric Acid
2. Hydrochloric acid (Muriatic acid)
3. Phosphoric acid
4. Acetic Acid

1. Sulfuric acid

Strength rating: 9/10
Sulfuric acid is an incredibly heavy-duty chemical used in plumbing for dissolving organic material in drains. One of its most potent and dangerous attributes is the heat generated when it comes in contact with water. While this is what helps break down the clog, it also requires careful consideration when using it in high concentrations. Most domestic drain cleaners will contain around 1% sulfuric acid, however, even these weaker solutions should be used with caution on plastic pipes.

Safety measures 

To safely use sulfuric acid, first open all windows in the room where the drain is to be unclogged to allow for proper ventilation. PPE, including gloves, goggles, and acid-resistant clothing will allow you to avoid burns and respiratory damage. The combination of water and sulfuric acid will get pretty hot, so be sure not to add too much at a time or it could potentially cause the pipes to melt. 

Uses

• Commercial kitchen drains: Can dissolve grease clogs in busy restaurants.
• Industrial plumbing: Useful for clearing out organic waste in factory settings.
• Bathroom sinks: Sulfuric acid can clear hair and soap scum blockages in heavily used bathrooms.

Recommended product

Santeen Drain Opener

2. Hydrochloric acid (Muriatic acid)

Strength rating: 8/10  
Muriatic acid is a type of hydrochloric acid, and the two are often used interchangeably. The key distinction is that muriatic acid is a diluted version of hydrochloric acid, containing small amounts of iron that give it a yellow hue, while hydrochloric acid is typically colourless or only slightly yellow. The strength of muriatic acid vary, with commercial versions containing up to 30% HCl. This makes it strong enough to tackle tough blockages, but it still requires careful handling.

Safety measures 

Always dilute muriatic acid with water before use (typically one part acid to 10 parts water). Always add acid to water, not water to acid.! This acid will cause burns to the skin and eyes, and its vapours can even damage your respiratory tract. Make sure to cover all exposed skin and eyes, wear acid-resistant gloves, and use a respirator and/or work in a well-ventilated area. It's important to note that combining HCI with other cleaning products, such as chlorine bleach, can produce toxic chlorine gas. Never mix cleaning products, as the results can be deadly! 

Uses

• Clearing mineral deposits: Effective for descaling pipes in older buildings.
• Outdoor drains: Ideal for breaking down organic matter and scum in external plumbing 
  systems.
• Sewer lines: Helps clear blockages caused by grease, hair, and debris.

Recommended product

Ace Liquid Drain Cleaner

3. Phosphoric acid

Strength Rating: 6/10
Phosphoric acid is less corrosive than hydrochloric and sulfuric acids, making it a safer option for certain applications. It's considered safe enough to be included in popular fizzy drinks, such as Coke and Pepsi! While it's best to be avoided in drinks, it's ideal for descaling and rust removal in pipes, as it effectively dissolves mineral buildup without posing as much risk to the plumbing materials. This makes it particularly useful in residential settings where older pipes might be more prone to damage from stronger acids.

Safety measures

While less corrosive than some of its competitors, care should always be front of mind when using any acid cleaner. This includes the basics of PPE, including gloves and goggles, as well as good ventilation wherever possible. 

Uses

• Rust removal: Safely removes rust from pipes and fixtures, restoring them without causing further corrosion.
• Hard water treatment: Prevents and treats mineral buildup in areas with hard water.
• Older plumbing: Ideal for cleaning and maintaining older pipes, minimizing the risk of damage while extending their service life.

Recommended product 

 Buckeye® Sparkle™ Multipurpose Acid Cleaner

4. Acetic Acid

Strength Rating: 4/10
Although technically vinegar, the last thing you'd want to do is add any acetic acid cleaners to your salad.  These cleaners often contain Acetic Acid at a concentration of 49%, which is far stronger than the vinegar you’d find in your kitchen. This concentrated white vinegar, classified as technical grade, is specifically formulated for cleaning purposes, not for consumption. Unlike the food-grade vinegar used in cooking, which typically has an acetic acid concentration of around 5%, this powerful cleaner is designed to cut through grease, grime, and mineral deposits.

Safety measures: 

The mild nature of acetic acid means it can be used more frequently and with less concern for damaging pipes. However, proper dilution is still necessary to ensure safety and effectiveness. Safety Measures, such as gloves and goggles, are recommended when handling acetic acid. If nothing else, it'll save your hands smelling like a UK fish and chip shop. 

Uses

• Limescale removal: Effective for removing limescale from taps, showerheads, and pipes.
• Fixture cleaning: Safe for regular cleaning of plumbing fixtures without causing damage.
• Minor blockages: Can be used to clear small clogs, especially when combined with hot water.

Recommended product

30% Acetic Acid Solution by DIYChemicals

Get your admin sorted and start experiencing the benefits of an organised business. Sign up for a 14-day free trial with Tradify. No credit card required. No commitment. Or pop over to one of our live demo webinars to see Tradify in action.