Inspecting Bottle Traps

Bottle traps, often referred to as decorative lavatory traps, are sleek, compact, and space-saving drainage solutions that fit well in tight areas. Bottle traps, also known as partition traps, are a type of plumbing trap that utilizes an internal partition to separate the house side from the sewer side. They resemble a small bottle, with an internal pipe designed to allow water to flow while retaining enough to form a seal that prevents sewer gases from escaping.

However, there’s a major issue: They don’t meet modern plumbing codes and are considered non-compliant. 

Here's what home inspectors need to know:

• Design and Functionality:
  • Bottle traps feature a single internal partition that maintains the water seal, preventing sewer gases from entering the living space.
  • Despite being made from corrosion-resistant materials, the internal partition can deteriorate over time.
  • A compromised partition may not result in visible leaks, making it difficult to detect a lost trap seal.

• Code Compliance:
  • According to the 2024 International Residential Code (IRC) Section P3201.5, traps with internal partitions, such as bottle traps, are not permitted.
  • Modern codes require traps to be self-scouring and allow for mechanical cleaning, criteria that bottle traps do not meet.
• Inspection Considerations:
  • While running water at fixtures, look at the trap. Bottle traps can be found in older homes or at decorative installations. A bottle trap is called a decorative lav trap. 
  • Recommend further evaluation by a plumber and replacement with a code-compliant trap, like a P-trap, to ensure safety and functionality.

Why This Matters:

Ensuring that plumbing systems adhere to current building standards is important for maintaining indoor air quality and preventing health hazards associated with sewer gas infiltration. Identifying and addressing non-compliant traps like bottle traps is a key aspect of a complete home inspection.