What is the maximum slope for a shower drain pipe?

Author: Gerald Wisozk  |  Last update: Tuesday, February 10, 2026

For optimal water drainage, it's advisable to ensure that the shower floor maintains a gentle gradient of approximately 2-4 percent. This corresponds to a decline of ¼ to ½ inch for every 12 inches from the shower enclosure to the drain.

Can a shower drain have too much slope?

The ideal slope of any drain line is ¼ inch per foot of pipe. In other words, for every foot the pipe travels horizontally, it should be dropping ¼ inch vertically. Many drains either have too little slope or too much slope. That's right, it is possible to have too much slope in your drain lines.

What is the maximum slope for a shower drain?

The finished floor shall slope uniformly toward the drain not less than 1/4 unit vertical in 12 units horizontal (2-percent slope) nor more than 1/2 unit vertical per 12 units horizontal (4-percent slope) and floor drains shall be flanged to provide a water-tight joint in the floor.

How much slope is too much for a shower?

If you're able to install the shower in a recessed fashion so that the built-in threshold is flush with the floor, it's also an option to slope towards the shower drain itself, flowing all splashed water towards the same drain. Don't forget to limit bathroom floor slope to ¼” per foot at most.

What is the maximum drain pitch?

the greatest quantity or amount possible, assignable, allowable, etc. the highest amount, value, or degree attained or recorded.

Plumbing Slope Rule and Why it is CRITICAL

What is code for slope of drain pipe?

Horizontal drain piping, including building drains and building sewers, shall be installed in uniform alignment at the following uniform slopes: not less than 1/4 inch per foot for 1-1/4 inch. 1-1/2 inch and 2 inch pipe size. not less than 1/8 inch per foot for 3 inch, 4 inch, 5 inch, and 6 inch pipe size.

How to slope a shower drain pipe?

The Optimal Slope for Effective Drainage

For optimal water drainage, it's advisable to ensure that the shower floor maintains a gentle gradient of approximately 2-4 percent. This corresponds to a decline of ¼ to ½ inch for every 12 inches from the shower enclosure to the drain.

What is the slope code for showers?

Floor or ground surfaces of showers shall comply with Section 11B-302.1 and shall be sloped 1:48 maximum in any direction.

What is the maximum slope for drain pipes?

According to plumbing code, drain pipe has to be sloped a minimum of 1/4-inch per foot and a maximum of three inches per foot or vertical.

How much angle does a shower drain need?

In a stall shower, the plumbing code requires the floor to be sloped one quarter (1/4) of an inch per foot in order to carry the water effectively to the drain.

What is the slope for shower waste pipes?

The “fall” or “drop” should be between 1/40 (1cm down for every 40cm across) and 1/110. Too steep (1/10) then the water runs quicker than the solids so doesn't wash them away (ugh!). Too shallow (1/200) and there won't be enough gradient to get rid of last night's curry.

What is the code for shower curb?

According to the IRC, the minimum height for a shower curb is 2 inches from the top of the drain. Specifically, the building code states: The curb shall be not less than 2 inches (51 mm) and not more than 9 inches (229 mm) deep when measured from the top of the curb to the top of the drain.

What is the slope for a curbless shower drain?

Slope of the shower floor

The International Plumbing Code (IPC) requires a slope of 1/4” per foot (IPC 417.5.

What is the maximum shower slope?

Note: The industry standard for shower slopes is a range of 1/4″ to 1/2″ per foot.

What happens if drain slope is too steep?

If the gradient is steeper than 1 in 40, the liquid may run faster than the solids in the sloping foul water pipe. This can leave solids stranded and eventually cause a major blockage in the pipework, which can be incredibly disruptive for public sewer connections and pump stations.

Are curbless showers a good idea?

Open-concept, or curbless showers are a concept that's growing in popularity – and for good reason. They offer accessibility – and lots of flexibility in design. And when we remove the barriers for our shower, we can also create a seamless look in the bathroom, making it look and feel bigger.

What is code for drain slope?

If you've ever wondered what the minimum slope for water drainage is, it is generally accepted that 1/4″ per foot of pipe run is the minimum for proper pitch on a sewer line.

How many toilets can be on a 4 inch drain?

4″ waste line can support 90 DFU's, Toilets can be 3–4 DFU's depending on how many gallons per flush. So, 22 toilets if they use a lot of water.

What is the slope per foot for shower drain pipe?

Pipes must slope slightly downhill to drain properly. The standard slope is anywhere from ¼ inch to 3 inches per foot depending on the use.

What is the proper pitch for a shower drain?

And, the “pitch” (the slope angle you're aiming for so that water will quickly run downhill to the drain from all parts of the shower floor) needs to be at least 1/8-in per linear foot of run (or, to really ensure no drainage dead spots, 1/4-in per foot of run).

What is the maximum allowable slope for an accessible shower floor?

While a threshold height up to ½″ (if properly beveled) is permitted, trench drains and other designs that allow a flush transition to the shower floor will provide easier access. Shower floors can slope to drains (a 1:48 maximum slope will help control water without impacting accessibility).

What is the proper slope for a drain pipe?

The slope of a PVC drain pipe should be at least 1/4 inch per foot for proper drainage. This means that for every foot of horizontal distance, the pipe should slope down by 1/4 inch.

What is the drainage angle for a shower?

The floor slope should be a minimum of between 1.5 and 2 degrees. This ensures the water will run to the drain efficiently and not cause water pooling. This gradient is also low enough to avoid the user feeling like they are standing on an uneven/sloped floor.

What is the minimum fall for a shower waste pipe?

The maximum fall for a waste pipe is 1 in 40. The minimum fall is 1 in 110 (apart from vertical pipes, but that's a different story). So pipes with a gradient between 1 in 40 and 1 in 110 should have adequate flow to prevent blockages from occurring.

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