Laying Sewer Pipe

They aren’t always fun to talk or think about but sewer pipes are an important part of any community’s water system, and it’s even more important they are installed and run properly to avoid backups into houses, drinking water or fresh waterways. When laying a new sewer pipe it’s vital to follow the appropriate steps, so here are the steps to follow in order to ensure the pipe is installed correctly and will not cause any issues in the surrounding community.

Determine Elevation

First things first: you have to know how far this sewer pipe is going, whether it’s connected to any specific fixtures or other extending pipes and, most importantly, the installation height. The general guideline is that sewage should run downhill and away from communities so you need to know the initial and final elevation, measured at the interior point of the connecting pipe. This can be done using a laser level, GPS or regular surveying equipment.


With the elevation and the pipe length known you will then need to figure out the pitch, or fall, of the sewer pipe. To do this, subtract both elevations and divide the horizontal pipe length into the difference in elevation. This gives you the drop per foot or meter of pipe. Something to keep in mind is that if the drop is greater than ¼” per foot won’t work while a slope that’s too small (less than 0.003” per foot) will not be adequate either. Ideally, for 4” piping, a 1/8” to ¼” per foot is recommended.

 Trenching & Bedding

You will need to dig a trench to lay the pipe itself in. Make sure you are following all safety procedures for workers completing the trench. It is recommended to grade the trench, and remove all loose dirt, so that the pipe is installed on a smooth service. You might have to use some bedding to provide the required support for the pipe being installed. The best bedding material to use is sand, but gravel is a close second should sand not be available to you. Make sure the bedding you do end up using doesn’t contain any sharp stones as these could puncture, or wear away at, the pipe and cause issues or require a replacement pipe prematurely.

Laying the Pipe

Once the area has been properly prepared it is time to lay the pipe. Usually it is recommended to start at the bottom and work your way up to the higher elevation. If the pipe has a bell end on it then the bell must be placed on the uphill side so as to reduce the possibility of leakage. Also, make sure to apply the PVC primer before applying any PVC glue.

Final Section

It is very possible that the last section of the run will only need a portion of a full pipe, but it’s important to know that you will also need other fittings to complete the pipe installation. Once the installation is complete, you should check along the run to make sure none of the previously installed pipes are leaking, cracked or otherwise damaged potentially from the installation.

If there aren’t any damages or leaks you can start covering the pipes with sand or gravel (as you used in your bedding material) making sure you cover the pipe by at least 10” with this material. Then the ground can be compacted – as appropriate for this kind of piping – and soil can be added on top. It is also important to put a warning tape just over the first layer of soil so that if this area needs to be excavated in the future others will be aware that there’s a pipe underneath.

Laying Commercial Pipes

Commercial buildings have very different needs in terms of utilities than houses do: often they use more electricity and water, or require the output of the systems to be different. When completing commercial renovations it’s important to know how this project is different from a residential one, and where it is the same.

Talk to a Professional

You know your business, and you’re very good at it. Plumbers know plumbing: they’re licensed, complete projects like this one all the time and can ensure your water supply system is completely up to code. When you decide to complete a renovation to your business it’s important to talk to a plumber right away as he or she will be able to assess the whole project, explain how their work fits in with other contractors work and when they will need to complete work by.

Have a Plan

Sometimes it isn’t enough to tell your contactors to take this and make it that: you need to know exactly what you want done. Some contractors will be able to take your vision and work with it, but most will want your input so have a plan: know when you want things done by, how you want them done, what kind of communication you want along the project, whether your contactors have discretionary spending, etc. Especially when it comes to laying new commercial pipes you need to be sure the plan and the timeline are in place so that you can coordinate the other contractors, or they can work in conjunction with each other.

Shut off the Water

In order for your plumber to remove the old pipes and start installing new ones the water has to be off. In this case it’s really important to know how the water supply to your business works: is it just one shut off, or can you shut off sections via a manifold system? This is something your plumber can do for you but if you’re concerned about time and want the plumber to start right away you could do this before the work even starts.

Follow the Code

Professional plumbers know that when completing any work everything has to be up to code. If this doesn’t happen you, as a business owner, could be in a lot of trouble. Do your own research and make sure you understand some of the building code so that you know the right questions to ask of your plumber.

A major commercial project is a big investment, and it means time your business is going to be closed to accommodate for the renovations. Make sure you have everything in place before work starts and be prepared for surprises, have a contingency plan where possible.

Making sure your plumber is licensed, insured and has a reputable business with experience laying commercial pipes can save you a lot of time and headache in the future, should anything go wrong.

Laying Pipes Underwater

 Pipes aren’t just underground – there’s a number of reasons pipes would need to be installed in or across bodies of water. However, paying pipes underwater poses several challenges for companies to install. There are different ways to install pipes underwater to ensure they are successful, don’t leak and will last for a long time.

Tow-In Pipelines

These pipelines are suspended in water via buoy and a tugboat, or two, will drag them into place. Once they are in the proper location the buoys will be flooded with water, or otherwise released, and the pipe will then sink to the floor of the body of water. This kind of installation can happen when the pipeline is above the water (surface tow), submerged in the water (mid-depth tow), already close to the bottom of the water (off-bottom tow) or it could be dragged along the floor of the body of water (bottom tow). The first three will work for all varieties of water, however a bottom tow is usually only used when the water is shallow and the floor is soft and flat so that no damage will be done to the pipe during installation.

S-Lay Pipelines

For this kind of installation, the pipe is slowly pushed off the back of a ship or boat while it moved forward in the water. The pipe will naturally curve downward through the water as the boat deploys more and more of it, and this will be done until the pipe reaches a pre-determined touchdown point which is usually the destination, or the floor of the body of water.

With this kind of installation it’s very important to ensure proper tension is used. If there’s too much tension on the pipe it could buckle or be damaged during installation, causing leaks or even breaking while still in use. An S-Lay installation can be used in water that is up to 6,500 feet deep, and can be installed at a rate of 4 miles per day.

 J-Lay Pipelines

While recognizing some of the major disadvantages to using a S-Lay Pipeline, the J-Lay is very appealing. This kind of pipeline puts less stress on the pipe by inserting the line into the water in an almost completely vertical position. The pipe will be lifted – usually via tall tower – off the back of a boat or ship and then inserted into the water. This pipe will only curve once – at the bottom of the water – unlike an S-Lay which has a double curvature and thus more chances for pressure, tension or breakage. Once it has hit the bottom of the water, it will take on the shape of the letter J which is what it was named for.

Since there is less tension and stress on this kind of pipeline it works in waters much deeper than an S-Lay would allow for, and it can withstand strong underwater motion or currents.

 Installing underwater pipelines is much different than ones underground because can create various pressure points, pipes weigh different amounts in water vs. on land and bodies of water can generally unpredictable. However, if the right kind of underwater pipeline is selected then it should last for many years and will be able to fulfill what is required of it. Regular maintenance, or even replacing sections of pipe, may be needed if the pipe is going to be use for a long period of time but as long as the installation is done accurately and maintenance is performed there won’t be any leaks or sections breaking prematurely.