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I have always believed that one of the most difficult talents to master in the plumbing and mechanical trade is being able to provide accurate plumbing isometric drawings. Let’s define what an Isometric Drawing is first before going into more detail. An Isometric Drawing is drawing details representing pipes, fittings, and fixtures at a 45° angle, in plain terms its the plumbing drawing scheme. The goal is to represent three-dimensional designs on two-dimensional drawings.

Having a well-done set of isometric drawings is like having a well-done set of instructions to build a swing set. When a good draftsmen, estimator or project manager is skilled enough to be able to provide the foreman or project superintendent with plumbing isometric drawings, the men in the field can do what they get paid to do. That’s to put in pipe and fittings.

It literally takes the thinking out of plumbing layout. As the industry transitions to digital media, computer programs can do any isometric pipe drawing for you. However, there is always a catch. If there is garbage that went into the plan view (most times it is garbage), then the isometric drawings will be worse. Quite often it’s not PE or a plumber that does the MEP drawings. Therefore, expect to see incomplete plans that are woefully inadequate to install a complete plumbing system. This guide will help you learn how to create and read plumbing isometric drawings.

Piping Isometric Drawing Reference Guide

While I was going through my plumbing stuff, I happened to come across one of the best references I have ever had and used. They are the isometric plumbing drawings for common residential building floor layouts, i.e., back-to-back bathrooms, kitchens, powder rooms in just about every configuration you can think of.

Wait, there’s more. Along with each drawing, there is a complete and accurate pipe and fitting takeoff for waste, vent, and water piping. Please contact me for a PVF takeoff for the waste and vent isometric drawings. There would be too many questions about pipe sizing and materials.

Here is how I will present this. Each Isometric drawing will be linked to a printable and sharable PDF. I will list the pipe and fitting take off after each drawing as well as an explanation of each fixture configuration. I can’t tell you how many times I’ve gone to these drawings for estimates, layout help, and fitting configurations. Therefore, I hope it helps you too.

Because these drawings are so well done, they can also be used to help you do your own isometric drawings in any configuration you see fit. I’ve always found these drawings put me in the right place spatially to envision how and where piping should go.

List of Plumbing Isometric Drawings

1.) Back to Back Bathtubs, Water Closets, and Lavatories

This is a plumbing isometric of the water piping for a condominium or apartment building. There are two bathrooms in the same unit or in separate units piped back to back. The water supply risers are coming in on one end of the bathrooms as you can see in the plumbing riser diagram.

Waste & Vent Piping

Plumbing Isometric Drawings | Back to Back Bathtubs | Water Closets | Lavatories

2.) Single Bathtub, Water Closet, and Lavatory

This plumbing isometric represents a battery of plumbing fixtures with just one bathtub, water closet, and lavatory. This would be used most commonly in a small apartment building where there is only one bathroom per apartment. It is possible there are two sets of water risers serving bathrooms. However, it can get expensive. Therefore, the architect/engineer usually likes to reconfigure a building to make use of as few risers as possible.

Bathtub

Plumbing Isometric Drawings | Single Bathtub | Water Closet | Lavatory

3.) Single Bathtub, Water Closet, and Lavatory with Utility Sink

This isometric represents a battery of plumbing fixtures with a little twist. In order to save pipe chase space, an architect may put the kitchen or utility room behind the bathroom. This way, you can use the water piping to pipe in a kitchen or utility sink.

Water Closet

Single Bathtub | Water Closet | Lavatory | Utility Sink

4.) Back to Back Bathtubs, Water Closets & Lavatories

This is a little different configuration. As you can see from the isometric drawing, the water-piping riser is coming up in the middle of the bathroom. Although the piping is similar, this will give you a visual idea of how the piping will look. Sometimes, due to building design, the pipe chase can be right in the middle of a stack of bathrooms. This is not an unusual design.

Single Lavatory

Bath to Back Bathtubs | Water Closets | Lavatories | Middle Riser

5.) Single Bathtub, Water Closet & Lavatory

This design is pretty self-explanatory. It shares similar configuration with the previous entry that featured a the water-piping riser in the middle.

Waste & Vent Piping

Single Bathtub | Water Closet | Lavatory

6.) Single Bathtub, Water Closet & Lavatory with Utility Sink

Please see #3 entry. The only difference is the water riser location.

Bathtub

Single Bathtub | Water Closet | Lavatory | Utility Sink | Middle Riser

7.) Back to Back Bathtubs, Lavatories & Water Closets

This is very similar to the #1 drawing. However, the lavatories and water closets are flipped.

Lavatory

Back to Back Bathtubs | Lavatories | Water Closets

8.)  Single Bathtub, Lavatory, and Water Closet

This is very similar to #2 drawing. However, the lavatory and water closet are flipped.

Single Water Closet

Single Bathtub | Lavatory | Water Closet

9.)  Single Bathtub, Lavatory with Utility Sink & Water Closet

This is very similar to #3. However, the lavatory and water closet are flipped.

Waste & Vent Piping

Single Bathtub | Lavatory | Utility Sink | Water Closet

10.) Single Bathtub, Lavatory, and Water Closet

This is very similar to #8. The only difference is that the water piping risers are in the middle.

Bathtub

Single Bathtub | Lavatory | Water Closet | Middle Riser

11.) Back to Back Bathtubs, Lavatories & Water Closets

This is similar to #7 with the water piping risers in the middle.

Utility Sink

Back to Back Bathtubs | Lavatories | Water Closets | Middle Riser

12.) Single Bathtub, Lavatory with Utility Sink, and Water Closet

This is similar to #9 sketch. However, you can locate the water piping risers in this one in the middle.

Lavatory

Single Bathtub | Lavatory | Utility Sink | Water Closet | Middle Riser

13.) Waste & Vent Piping for Back to Back Lavatories, Water Closets, and Bathtubs

You can use this waste and vent isometric for PVC with no-hub cast iron or copper. However, with most buildings trying to cut the budget, PVC or No-Hub is usually the way to go. These materials are budget friendly and learning how to fix leaking PVC pipe joint can be quite easy even for entry-level homeowners.

Single Water Closet

Back to Back Lavatories | Bathtubs | Water Closets | Waste & Vent Piping

14.) Waste & Vent Piping for Single Lavatory, Water Closet, and Bathtub

Waste & Vent Piping

Single Lavatory | Water Closet | Bathtub | Waste & Vent Piping

15.) Waste & Vent Piping for Back to Back Water Closets, Lavatories, and Bathtubs.

Back to Back Water Closets

Back to Back Water Closets | Lavatories | Bathtubs | Waste & Vent Piping

16.) Waste & Vent Piping for Single Water Closet, Lavatory, and Bathtub

Bathtubs

Single Water Closet | Lavatory | Bathtub | Waste & Vent Piping

17.) Waste & Vent Piping for Single Water Closer, Lavatory w/Utility Sink & Bathtub

Lavatories

Single Water Closet | Lavatory | Bathtub | Waste & Vent Piping

Plumbing Drawing Final Word

As always, thanks for reading and I sincerely hope this helps. I know it helped me like crazy over the years. If you have any further questions, you can contact me at skavanaugh@todaysgrowth.com.

Here is the Slideshare for the entire set of drawings.

Free Help with Plumbing Isometric Drawings from Sean Kavanaugh.

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