Understanding Drum Traps in Older Homes

Drum traps are a type of plumbing trap that were commonly used in older homes, particularly those constructed between the 1920s and 1950s.

While they are no longer installed in modern houses, many older homes still have drum traps in place.

This article will provide an in-depth understanding of drum traps, their advantages and disadvantages, and what to do if you have one in your home.

What is a Drum Trap?

A drum trap is a cylindrical plumbing device typically used beneath bathtubs or bathroom floors to prevent sewer gases from entering the living space.

They are designed with a vertical centerline and a removable cover plate for easy access. Drum traps come in various shapes, sizes, and materials, such as cast iron or lead.

Drum Trap Components

A drum trap consists of a cylindrical container with two pipes connected to opposite ends.

One pipe is the inlet, which connects to the drain system, while the other is the outlet that carries water away.

The cover plate on top of the drum trap can be unscrewed to access the interior for cleaning or maintenance.

Drum Traps and Venting

Unlike modern P-traps, drum traps do not have venting systems. Plumbing traps are required to have vents to protect the water seals from being damaged.

Without proper venting, toxic sewer gases and foul odors can seep into the living space, posing serious health risks.

Pros and Cons of Drum Traps

Although drum traps are no longer used in new construction, they do offer some advantages, particularly for those living in older homes.

Pros

1. Preserving the Original Design: Homeowners who wish to maintain the original design of their older homes might prefer to keep the drum trap in place, especially if the plumbing system is close to the floor.
2. Preventing Sewer Gas Leakage: Drum traps hold a large volume of water, which helps to prevent sewer gas from entering the living space.
3. Blocking Large Debris: Drum traps can prevent large items from entering the water pipes, which can cause obstructions and clogs.

Cons

1. Not Self-cleaning: Unlike P-traps, drum traps are not self-cleaning or self-scouring, making them prone to clogging due to the accumulation of solids at the bottom of the trap.
2. Difficult to Clean and Maintain: Drum traps can be challenging to clean and unclog, as their location often makes it difficult to access the cover plate. In some cases, the floor may need to be cut to access the lid.
3. Risk of Collapse: Drum traps made from lead, a soft and easily pierced material, can collapse if the cover is removed or tightened too forcefully.

Drum Trap Legality: Are They Legal?

Drum traps are not illegal, but they are generally not allowed in modern construction due to various reasons, such as their lack of venting and their tendency to clog.

Plumbing codes for different states in the United States vary, so it is essential to research your state’s plumbing code regarding drum trap usage and replacement.

Plumbing Trap Codes

Here are some examples of plumbing codes related to drum traps in different states:

Minnesota

• Minnesota State Plumbing Code (4715.0200, “s”): “Each fixture shall be provided with a separate, accessible, self-scouring, reliable trap placed as near to the fixture as possible.”
• Minnesota State Plumbing Code (Section 1004.1): “Drum and bottle traps shall be installed for special conditions.”
• Minnesota State Plumbing Code (Section 4715.0960): “Drum traps shall only be installed when permitted by the administrative authority for special conditions (laboratory tables, dental chairs, etc.).”

Florida

• Florida Plumbing Code (FPC-1002.2): “Fixture traps shall be self-scouring. Fixture traps shall not have interior partitions, except where such traps are integral with the fixture or where such traps are constructed of an approved material that is resistant to corrosion and degradation. Slip joints shall be made with an approved elastomeric gasket and shall be installed only on the trap inlet, trap outlet, and within the trap seal.”
• Florida Plumbing Code (FPC-1002.3): “Exception: Drum traps used as solids interceptors and drum traps serving chemical waste systems shall not be prohibited.”

Before purchasing an older home with a drum trap, it is essential to check your state’s plumbing codes to determine if its usage is still legal.

Cleaning and Unclogging Drum Traps

If your home has a drum trap, it is vital to clean and maintain it regularly to prevent clogs and issues.

Most plumbing experts recommend cleaning your drum trap at least four times per year or monthly if there are many people living in the home.

How to Clean and Unclog a Drum Trap

1. Locate the Drum Trap: Drum traps are typically found near the drain hole and underneath the floor, making them difficult to access without cutting sections of the floor.
2. Locate the Central Nut: Find the central nut or grip tip on the threaded cover, which may or may not be visible. Use an adjustable wrench to turn the central nut counterclockwise to remove the cover. Apply lubricant spray if necessary and repeat the process until the cover is removed.
3. Inspect the Rubber Gasket: Check the rubber gasket on the cover for wear and tear. Replace it if necessary.
4. Clean the Drum Trap: Use your hand, rubber gloves, or tools like needle-nose pliers to remove accumulated debris from the trap. Run hot water through the trap for a few minutes to loosen and clear any remaining debris.
5. Use a Plunger or Chemical Drain Cleaner: If necessary, use a plunger to clear any remaining debris. Alternatively, use a chemical drain cleaner or a mixture of vinegar, liquid dish detergent, hot water, or salt and hot water to dissolve or loosen materials narrowing the pipes. Leave the solution overnight before flushing it out.
6. Open the Faucet: After cleaning the drum trap, open the faucet to ensure continuous water flow. If the water does not flow continuously, you may have a clogged pipe and should consider contacting a professional plumber.

Conclusion

Drum traps are a type of plumbing trap found in older homes that can be challenging to clean and maintain.

While they are not illegal, they are generally not allowed in modern construction due to various issues, such as their lack of venting and their tendency to clog.

If your home has a drum trap, it is essential to clean and maintain it regularly to prevent clogs and issues.

Before purchasing an older home with a drum trap, check your state’s plumbing codes to determine if its usage is still legal.

If you encounter problems with your drum trap, consider contacting a professional plumber to help with cleaning or replacing the trap with a modern, self-cleaning P-trap.