Unexpected issues that pop up in the middle of a big remodeling project can be costly and time-consuming to fix. Minimize the risk of surprises by thinking ahead and drawing a plumbing plan.

By BH&G Editors
Updated September 30, 2020
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A well-planned diagram is essential for any remodeling project that involves major plumbing work. If you're renovating your kitchen or adding a new shower to an existing bathroom, for example, drawing up a plumbing plan allows you to map out the system beforehand, which will help ensure the process runs as smoothly as possible. Professional plumbers usually map a plumbing job in painstaking detail to prevent surprises during the project, and you should too if you're planning on completing the work yourself.

A plumbing drawing illustrates the system that will bring water in and take waste back out. It typically includes water supply lines, drains, vent pipes, valves, and fixtures such as toilets and sinks. These plans often use a variety of official plumbing symbols to denote different elements, and it's fairly easy to produce plan views and riser drawings either by hand or using a computer.

gray bathroom with white tile
Credit: Adam Albright

Making detailed drawings will save time and expenses later. Also, drawing the project helps you think through the job in detail, which can enable you to spot something that you might otherwise overlook. If you have all the necessary materials noted in the plan, it will almost certainly minimize extra trips to the plumbing supply store. A clear, professional-quality plan can also be especially helpful for projects that require a plumbing permit. Although a plan might not be required in order to obtain a permit, it will likely make your initial meeting with the building department more productive. Be sure to check your local plumbing codes before you begin.

plumbing symbols

How to Draw a Plumbing Plan

A plan for new plumbing starts with a map of the existing plumbing. Use color codes and these universally recognized symbols on your drawings to clearly denote each component of your plan.

If you have architectural drawings, make several photocopies of them. Otherwise, make several copies of an accurate scale drawing of the room. A gridded straightedge will help you draw parallel lines. You'll also need color pencils, an eraser, and a 30-60-90-degree triangle. Use grid paper and establish a scale, such as 1/2 inch equals 1 foot. Drawing to scale makes it easy to note any problems with the layout. It also helps in estimating materials.

To make a plumbing plan, first draw all fixtures to scale size and make sure they are not too close together. Mark the drain lines and vents for the fixtures, then add the supply lines. Make riser drawings to show vertical pipe runs as well.

Indicate pipe sizes and the exact type of every fitting so the inspector can approve them. Mark locations for valves, including stops at fixtures, and specify the type of valve. Make a shopping list of materials based on the drawings.

Elements of a Successful Plumbing Plan

To help your DIY remodel go smoothly, make sure your plumbing plan includes these key elements.

plumbing plans for bathroom
Credit: Dave Toht

Key Coding

It's a good idea to code your map to keep the different elements straight. Show drainpipes with solid lines and supply lines with broken lines. Indicate vertical runs with notes on the overhead view. Mark hot and cold supply lines with colored pencils and color-code drains and vents. Point to pipe sizes with a curved leader line to avoid mistaking the leader for a pipe. You might need to draw several versions of the plumbing plan before you get all the details right.

plumbing plans for bathroom with dwv
Credit: Dave Toht

DWV Elevation

A drain-waste-vent (DWV) elevation describes the system that will carry water, waste, and air out of the house. This part of your plumbing plan should note the upward path of the stack, vents, and revents; the length of drainpipe runs; and traps. Its primary purpose is to show how the fixtures will be vented. It doesn't have to be drawn over an architectural drawing, although that can be helpful for reference.

supply drawing for plumbing in bathroom
Credit: Dave Toht

Supply Drawing

A supply drawing indicates the estimated length of supply pipes. Be sure to include the pipe size as well. The main purpose of this drawing is to determine the minimum size of the pipes. Refer to this plumbing plan as you make your shopping list of materials to ensure you purchase the right sizes and lengths.

Comments (1)

Anonymous
January 29, 2019
I sure got fooled when i asked how to plumb a shower,these pictures just confused me more,i need a real good picture of where and how everything fits together,from the studs to the shower in working condition,help i have no experience and no help!!!