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What Causes A Water Main To Burst?

A water main is a large pipe that carries water from a city’s water treatment plant to homes and businesses. Every public water supply system has a water main. Water mains are usually made of cast iron, ductile iron, or steel. They are buried under the ground and are typically four to six feet in diameter. The pipes that connect homes and businesses to the water main are called service lines.

As previously said, water is supplied through huge pipes, or water mains, that are tucked beneath sidewalks and roads and lead to various locations. Water mains are connected to houses, businesses, and apartment complexes via smaller pipes, also known as water lines. Water mains normally fall within the purview of municipal governments when it comes to maintenance and repair. In contrast, the water lines are the responsibility of the property owner.

At O’Grady Plumbing, we have the expertise for water main repair and replacement. Click here to go to our main service page.


How do water mains work?

Water is transported from a treatment facility to the key water-using regions of a town via arterial water mains, also known as primary feeders. Secondary feeders, often known as water lines, link to the mains and are typically smaller in size. In order to give potential water consumers access to service connections, these pipes are often built inside public rights-of-way.

There are several kinds of water distribution networks, but these tubes are often set up in a gridiron design to allow water to circulate in linked loops. As a result, any broken pipe portions may be located and repaired without causing any disturbance to the community’s water supply. Dead-end patterns are another tool that may be employed. These patterns prevent circulation, making the water they deliver more prone to taste and odour issues brought on by blockage.

Considerations for Water Mains

Pipelines for the water supply must be resistant to corrosion and external and internal stresses. These pipelines are under strain from internal water pressure brought on by the weight of the earth and any possible above-ground traffic. It may be necessary for water mains to withstand water hammer forces. The water supply system may experience pressure waves if valves close too rapidly.
Internal and exterior corrosion in water mains and water lines is a crucial factor to take into account. For example, if the pipes are constructed of metal, they may corrode inside if the water pumped through them is corrosive. External corrosion might occur if the soil around the pipes is corrosive.

Causes of Water Main Damage

There are two types of water mains: distribution mains and transmission mains. Distribution mains are the pipes that deliver water to homes and businesses, while transmission mains are the large pipes that carry water from a treatment plant to distribution mains.

Water main breaks can occur for a variety of reasons [1]:

Freeze/thaw cycles:

Water mains are buried under the ground, and as the temperature fluctuates, the ground can shift and put stress on the pipes. This can cause them to crack or break.


Contractors, utility employees, and even homeowners may unintentionally damage water lines when they dig using their digging equipment. Simple tools like a shovel or, more frequently, powerful excavating machines can cause damage. It is impossible to stress the importance of thorough planning and diligent analysis before setting out for any excavation.


Over time, the pipes can corrode and weaken, which can eventually lead to a break.

Ground movement:

Earthquakes, landslides, and other ground movements can damage or break water mains. So, areas prone to seismic activity are at a higher risk of water main breaks.

 Pipe corrosion:

 Pipe corrosion is one of the most common causes of water main breaks. As pipes age, they become corroded and brittle, which can lead to breakage.

 Age and composition of the pipe

Older pipelines are more susceptible to breakage than new ones. For instance, cast iron was frequently used for water main construction before 1980. Cast iron can be fragile and does not easily expand and shrink with temperature changes. The pipes are prone to cracking when this takes place. There are also some older clay sewer pipes. Additionally, this substance is easily broken down. In order to prevent problems like these in the future, water mains are frequently made of ductile iron or plastic pipes nowadays. If your pipes are many decades old, it might be time to assess their condition.

Pressure shifts

There are several ways in which the pressure inside a water main might fluctuate. Temperature variations, often known as thermal expansion, are one of the most common methods. The pipes stretch and compress as the earth around them freezes and warms, occasionally rupturing. When fire hydrants are opened or closed too fast, pressure shifts can also happen. This can cause breaks in the water main as well.


 Floodwaters can damage or break water mains, contaminate water supplies, and create health hazards. If you live in an area that is prone to flooding, it’s important to be prepared.

If you see broken water main, it’s important to report it to your local water utility so they can make the necessary repairs. In the meantime, here are a few things you can do:

  • If the break is on your property, turn off your water at the main shutoff valve. This will help prevent further damage to your home or business.
  • If the break is in the street, do not attempt to repair it yourself. The water mains are a city responsibility, and only trained professionals should work on them.
  • In either case, contact your local water utility to report the break and schedule repairs.

Here are a few things you can do to protect your property:

  • Elevate important items such as electrical panels, furnaces, and water heaters to above the flood level.
  • Install check valves in the sewer drains to prevent floodwaters from backing up into your home or business.
  • Have a professional waterproof your basement or crawlspace.
  • Store emergency supplies of food, water, and other essential items in a safe location.

If you experience flooding, it’s important to take action immediately to protect your property and avoid health hazards. If possible, turn off the electricity to your home or business. This will help prevent electrocution or fire. If floodwaters have entered your home or business, be sure to wear protective clothing, including gloves and boots, to avoid coming into contact with contaminated water. You should also:

  • Remove any standing water from your property as soon as possible.
  • Throw out any food that has come into contact with floodwaters. 
  • Disinfect any surfaces that have been in contact with floodwaters. 
  • Dry out your property as soon as possible to prevent the growth of mold and mildew.

If you have any questions or need assistance, please don’t hesitate to contact O’Grady Plumbing Service. We’re here to help!

How long do underground water lines last?

Underground water lines have been estimated by experts to last anywhere from 40 to 100 years. However, there are many factors that can affect the longevity of your water line, such as the materials used in construction, the surrounding soil conditions, and the amount of usage the line gets. If you’re concerned about the condition of your water line, it’s always a good idea to have it inspected by a professional. O’Grady’s plumbing service is happy to help you with any questions you may have. Give us a call today!

Installation tips to prevent future water main line issues

  • Use high-quality materials that are appropriate for the job. Your O’Grady professional can help you select the best materials for your needs.
  • Work with a qualified contractor who has experience installing water lines.
  • Make sure the contractor excavates carefully to avoid damaging the line.
  • Make sure the line is properly supported and backfilled to avoid shifting or settling.
  • Inspect the line regularly to catch any problems early on.

If you’re having problems with your water main line, O’Grady plumbing service is here to help. We have the experience and expertise to get the job done right, and we’re committed to providing outstanding customer service. Give us a call today!

What to do if you think your water main is leaking?

If you think your water main is leaking, it’s important to act fast. A leak can not only lead to costly repairs, but it can also cause serious damage to your property. If you see water seeping from the ground or notice a drop in water pressure, give us a call right away. We’ll come out and take a look to see if there’s a problem with your water main. O’Grady’s plumbing service is here to help with all your water main needs. Give us a call today!

Installing a Water Main

The process of installing a water main is complex and, as such, should be left only to professionals. [2] The steps involved include:

1. Excavation 

Excavation is the first and most important phase in the installation of a water main. In order to install the pipe, we must first dig a channel. Before beginning this procedure, there are some factors to bear in mind first:

  • The amount of traffic that will cross the pipe
  • the soil type
  • The size of the pipe being used
  • The depth of any other utility lines that the water main must pass through or parallel with.

2. Bedding

Bedding is creating a platform for the pipes to be placed on. When bedding, a few things need to be considered. First, to ensure that the pipe’s barrel has continuous, solid support over its entire length, the bottom of the trench needs to be carefully levelled and compacted. Also, a levelling board is used to check the slope and ensure there are no voids or high places.

3. Putting in the Pipe

The pipe may be inserted into the trench once it is prepared. Laying pipes can be done in several general ways. But before that, an inspection is necessary to look for deterioration in a pipe. It is advisable to delete any substandard sections. Before installation, it is important to clean the area to get rid of any dirt, grease, oil, or other objects. The hypochlorite solution is advised to clean effectively and quickly. The pipe must be lowered manually or with the aid of machinery into the trench without rolling it. While installing the pipes, it is important to keep the interior of the pipe clean while it is lying since pipes are often held during placement by a sling in the middle.

4. Attaching Pipes

This is a delicate step in the installation of the water main. To prevent leaks and to guarantee the water main service’s efficient operation and lifespan, it must be done properly. The kind of pipe material and the type of joints affect the connecting techniques. Where pipes will be joined, bell holes must be manually drilled. This will make it possible to install the joint. Depending on the pipe and joint used, the size of the bell hole will change. A bell hole that is too big might put a strain on the pipe.

5. Connecting with Other Mains

To connect to the current mains, there are two options. Both a fresh tee and a pressure tap are options for the installer when connecting.

6. Tee Connection

The mains are modified to accommodate a tee fitting. Mains already in place must be disconnected for a number of hours. In order to remove a segment, a piece of the main must be cut or snapped at its outside borders. In the middle of them, a third cut is made. The pipe will effortlessly rupture if struck with a hammer in the middle.

7. Pressure Taps

Considering their benefits, we strongly advise the use of pressure taps. Here are just a few of those benefits:

  • Customers are not inconvenienced by the water being shut off.
  • Decreases the likelihood of polluting the water system.
  • The area’s fire protection is protected and will still be operational.

Making a pressure tap is substantially quicker as compared to inserting a tee after taking into consideration the time needed to close valves and alert consumers.

While there are many reasons why water mains can burst and each one of them is as stressful as the next, it is important to know that getting your water main installed properly and maintained by a professional can help reduce the risk of it bursting. O’Grady plumbing services is experienced in both the installation and maintenance of water mains, ensuring that your home or business has the best chance possible of avoiding a stressful and costly burst water main.

So, get in  touch with O’Grady plumbing services today to ensure that your water main is up to code and won’t cause you any headaches down the road.


  1. What Causes Water Main Leaks?
  2. Fix Leaky Pipes in Buildings.

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