Have you ever wondered, “What is rough plumbing?” You’ve probably seen plumbers drilling holes in walls and fitting water supply and drain pipes during the early stages of construction, and you may wonder why they do so. Well, this is what’s referred to as rough-in plumbing.

‘Rough-in’ is usually the first step of installing plumbing materials (such as pipes) in any type of new construction. It requires proper planning and the expert fitting of plumbing lines to connect the building with its supply and waste systems. It’s a vital step during new construction.

This guide explores everything you need to know about rough-in plumbing, from how it works to why it’s essential.


What is rough plumbing?

Here’s what you need to know if you have the burning question of “What is plumbing rough-in?”

When planning new construction, rough-in plumbing is a crucial component of building skeleton structures. Before builders finalize and complete a structure, they allow plumbers enough time to install any pipes correctly to avoid structural problems that might arise later.

The rough-in stage of construction is the phase that occurs after basic framing. During this stage, electricians install wiring supplies, masons fix window and door frames, and most importantly, plumbers fit pipes. This involves laying pipes for drains and connecting water supplies.

In most cases, rough-in plumbing occurs before construction contractors pour in the concrete slab. Plumbers must first install waste lines since the pipes that drain away wastewater are usually larger than the supply lines. After that, plumbers will install the water supply pipes.

Rough-in plumbing requires careful planning of bathrooms, kitchens, and laundry rooms. This is due to the fact that these locations handle a lot of water, so the supply and drain lines must be intact. These plumbing systems also require pressure testing to identify potential leaks. 

Finally, inspectors must check the integrity of the roughed-in plumbing system before construction continues. They must cover the drain lines to stop debris from entering.

The input that goes into rough-in plumbing is complex and makes DIY impossible. Therefore, hiring a professional plumber from companies like J. Blanton Plumbing to complete the rough-in job is essential.


What happens during rough-in plumbing

Now that you know the answer to the question, “What is a rough in plumbing,” it’s also vital to understand what happens during the process. It goes beyond installing water supply lines and drain pipes. The plumber must be strategic when fitting pipes onto floors and walls.

Here are some things that a plumber will be working on when completing rough-in plumbing.

  • Running vent stacks to the roof
  • Connecting supply pipes as required
  • Routing supply pipes through wall cavities
  • Connecting drain lines to the sewer line or septic system
  • Excavation and installation of underground pipes from utility connections

No fixtures or end elements (such as sinks, taps, and toilet flanges) get installed in this phase. Since there are no coverings, inspectors can easily test the plumbing system’s integrity.


What is rough-in plumbing: factors to consider

There are many crucial things to consider during rough-in plumbing. Here are the essential things to note.


Make sure you’re setting wastewater drain line pipes in a position that slopes downwards for proper draining. After all, water and waste will not drain when pipes are angled incorrectly. The angle should not be too steep, however, since it may raise concerns about pipes draining too fast.


Plumbers must vent wastewater systems to ensure that the waste is rid of securely and efficiently. Also, the waste pipes must be larger than the actual water supply lines to provide enough space for waste movement.


Avoid making too many or bigger pipe holes on timber frames, as it can compromise the integrity of the timber frame, weakening the house. Instead, you may have to reinforce the drilled frame to restore the structure’s integrity.

Securing the pipes

Secure the pipes correctly to prevent the “water hammer” effect, which involves loud noises coming from the pipes when water and air move through the tubings. The hammering noise can be highly disruptive. More importantly, unsecured water pipes can easily break.

Wrapping up

Once the rough-in plumbing stage is complete and the inspector has approved the plumbing system, professionals can then move to the finish-plumbing phase based on construction procedures, which involves installing the actual plumbing fixtures.


What is a plumbing rough-in: how long it takes

Rough-in plumbing usually takes a few days to finish, scheduled for completion just before the building inspector arrives. Conducting it too early can be disruptive since all workers must wait for the inspection to be done before progressing with the project. Meanwhile, doing it too late may force the inspector to postpone the actual inspection.

On average, rough-in plumbing should take 3 to 5 days to complete the entire process, unless other factors extend the duration. For instance, major construction projects, like multifamily apartments, need more time for plumbing rough-in since they have multiple bathrooms.

Whether the construction project is smaller or larger, plumbers must coordinate with many stakeholders to ensure that all plumbing is completed on time. This helps to avoid conflicts with inspectors or other contractors, saving time and money.


Contact J. Blanton for help with rough-in plumbing

We hope this article has answered the question of “What is rough plumbing?”. The success of rough-in plumbing depends on the expertise of those who do the job. Unlike other DIY home improvement projects, rough-in plumbing can be quite complex. This construction project can be incredibly technical and requires expertise for completion.

Consider hiring a professional plumber to handle the rough-in construction phase when building new construction. The good news is that J. Blanton Plumbing has a team of experts who can help establish and fix your building’s plumbing, from the rough-in phase to the completion stage. Contact us today!