What is the maximum spacing between cleanouts?

Under IPC 708, horizontal drainage piping 4 inches and smaller needs a cleanout at least every 100 feet, and piping larger than 4 inches at least every 150 feet. The distance is measured as developed length along the pipe, including the equivalent of fittings.

Where else are cleanouts required?

Besides the spacing rule, a cleanout is required at or near the base of each waste or soil stack, at each change of direction greater than 45 degrees, and where the building drain connects to the building sewer. This tool counts all of these.

Does a direction change always need a cleanout?

A change of direction greater than 45 degrees requires a cleanout so a snake can reach the bend, though a single cleanout can serve more than one nearby fitting if it provides access to all of them. Aggregated 45-degree offsets that together exceed 45 degrees are treated as a direction change.

What is the building drain cleanout?

It is the cleanout where the building drain meets the building sewer, often a two-way cleanout that lets a snake run both upstream into the house and downstream toward the main. It is one of the most important access points and is required on essentially every system.

Why do the rules differ between code editions?

The exact spacing distances and the over-4-inch threshold shift slightly between IPC cycles and local amendments. This tool uses the common 100 ft and 150 ft values, but always confirm against your adopted code edition before submitting for inspection.

Drain Cleanout Spacing & Location Calculator

Cleanouts are the access points that let a drain be snaked when it clogs, and the IPC is specific about where they must go. This calculator applies IPC Section 708 to count the minimum cleanouts a drainage run needs and tells you exactly where each one belongs.

How it works

Required cleanouts come from a spacing rule plus a set of fixed locations:

max spacing   = 100 ft  if pipe ≤ 4 in,  150 ft  if pipe > 4 in
intermediate  = ceil(run length / max spacing) − 1
fixed needs   = 1 building-drain cleanout
              + 1 per waste/soil stack base
              + 1 per direction change > 45°
total         = fixed needs + intermediate

The developed length is measured along the pipe, so add fitting equivalents on long runs. Any single run longer than the spacing limit triggers intermediate cleanouts.

Example and notes

A 250 ft, 4 in building drain with three direction changes and one stack needs two intermediate cleanouts (250 ft over a 100 ft limit), one at the building-drain junction, one at the stack base, and three at the bends — six in all. Each cleanout must be accessible and sized to the pipe; cleanouts on pipe 6 inches and smaller are full pipe size. Always verify against your adopted IPC edition and local amendments, which can change both the spacing and the threshold diameter.