Pigging Municipal Water Mains: Process & Benefits
It’s essential for municipal pipelines to be cleaned routinely to ensure the quality of water people receive meets health and safety standards. Yet, even though many realize the importance of pipeline cleaning, not many know how pipelines and municipal water mains are cleaned.
One of the most reliable and popular methods of cleaning municipal pipelines involves a process called pigging. Many municipalities use this technique because it removes tuberculation, biofilm and other sediment very effectively; much more so than flushing.
There are numerous benefits involved with pigging water lines, and luckily at American Pipeline Solutions, we understand this process. In this article, we will discuss these benefits alongside the process involved with pigging water mains for municipalities. This article will also look at the latest development in pigging technology, Ice Pigging™.
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What Is the Process of Pigging Water Mains?
The exact process of pigging water mains will depend on the type of pigging chosen, yet there is a generalized process that many pigging procedures use. Initially, a “prover pig,” which can be equipped with a location device, will be deployed into the water pipeline to determine if there is an obstruction. The material of this pig is very light in density, so if it does encounter a solid obstacle, it will break apart and not become lodged inside the pipe.
After this has been done, and based on the condition of the prover pig, a specialized cleaning pig will be inserted, where it will travel to remove sediment while being propelled by pressure to the exit access endpoint. The sediment and pigging material will be removed and safely discarded at the endpoint.
Below we have given a detailed step-by-step look into how pigging a municipal water main (above was a summary) is done so that you can understand the process better.
A thorough municipal pipeline system evaluation and performance baseline will be completed.
A team of experts will work together using their evaluation and performance baseline to develop a work and contingency plan.
After the work and contingency plan have been done, the next step will be to isolate the municipal water line to be cleaned.
Once the pipeline has been isolated, a “prover pig” will be inserted and run through the water line to prove flow.
When the “prover pig” has been run through the waterline, a team will examine it and decide the size and type of cleaning pigs based on the “prover pig’s” condition. They will also take into account the conditions of the pipeline.
After the pig type has been chosen, it will be run through the municipal water pipeline. After each subsequent run, the condition of the cleaning pig will be visually analyzed. Based on the condition of the pig, a similar one may be run, or the next size/material type of pig will be run; this is known as the progressive pigging method.
Once our team has determined that a pipeline is clean based on the condition of the most recent pig or the amount of dirty water accompanying the pig, the water line will be flushed so that any loose debris is removed.
If the water supply needed to be cut, it would be restored after the line had been flushed. The team will ensure the system is fully operational after the restored water flow.
Usually, the last step in confirming a municipal water main has been cleaned successfully is to document the results and compare them to the baseline performance results. Depending on the comparison of the results, it might be necessary to run a secondary pigging operation.
Factors To Consider Before Pigging Water Mains
Although, for the most part, the pigging process is straightforward, several factors need to be considered before pigging can commence. Below we have briefly discussed these factors to further help you understand the process of pigging water lines. We have briefly touched on some of what we mentioned below in the above section.
1. Planning
Planning is the most important part of the pigging process. Before a municipal pipeline can be pigged, workers must determine the fittings and pipe design. The workers at American Pipeline Solutions know that the overall design of the water main will affect the insertion and retrieval points. For many water mains, pigs can be launched and retrieved through fire hydrants, limiting the need for holes to be dug.
Additionally, securing data on the water main will help workers learn if there are any obstructions that might block the pig from completing its task, such as a half-opened valve.
2. Pig Selection
Besides planning, it’s crucial to determine the type of pig needed and the required length (usually 1.5 times the length of the pipe section being cleaned). The types of pigs used will be based on the type and age of the pipe, current flow rates, type of debris in pipe (biofilm, tuberculation, etc), and many other variables.
3. Type of Pigs Needed
There are many different types of pigs that can be used to clean municipal water mains and pipelines. Below we have briefly listed the types of pigs that could be needed when cleaning a municipal water main.
A prover pig: Light in density, these are used due to their ability to break apart when met with an immovable obstacle
Durafoam pig: Medium density and usually coated, these pigs are used in majority of cleaning and are effective at removing most types of debris
Wire brush pig: Heavier density pig wrapped in wire brushes used to remove heavier debris such as tuberculation
Ice pigs: See Ice Pigging™ service page
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Certified solutions for inspection, pre-commissioning, cleaning, internal coating, ice pigging™, mapping, and turnkey pipeline projects—maximizing safety and reliability at every stage.
What Are the Benefits of Pigging Water Lines?
There are several benefits of pigging municipal water mains. For example, when a municipal water main line is pigged, mud, sediment, calcium carbonate, scale, manganese iron, bacteria, biofilms, and other contaminants are removed.
In addition to this, traditional pigging can navigate a short radius, most valve types, and tees to ensure every inch of a pipe is cleaned to restore pressure and optimal water flow and ensure better water quality.
The pigging process is also incredibly effective at restoring a water main to almost its original conditions. Furthermore, traditional hydraulic pigging is still often preferred because one of its most significant benefits is that it can clean a wide range of pipeline diameters of up to 95 inches.
Notable Mention: Ice Pigging™ Benefits
Although traditional pigging processes are useful for cleaning municipal water mains, Ice Pigging™ has become a popular choice in recent years. This is because Ice Pigging™ is incredibly cost-effective and uses up to 50% less water.
Additionally, Ice Pigging™ has the added benefit of never getting stuck in a pipeline during cleaning. If it encounters an obstacle, it will simply melt. This is why Ice Pigging™ also causes no infrastructure damage.
Moreover, Ice Pigging™ has numerous applications. This pigging process also has an impressive three-mile daily coverage limit, has a short water interruption timeframe (1-4 hours), and is highly effective at removing sediment.
How Often Should Municipal Water Mains Be Pigged?
The frequency of pigging municipal water mains depends on several factors, including the age of the pipeline, water quality goals, and local environmental conditions. In general, many municipalities benefit from routine pigging every 3 to 5 years to prevent buildup, maintain flow efficiency, and avoid long-term issues like biofilm formation or corrosion.
If a city is dealing with frequent water discoloration complaints, reduced flow, or sediment issues, more frequent pigging may be recommended. In new developments or systems recently upgraded, pigging may also be part of the commissioning process to clear debris before the lines go fully online.
Municipalities often combine pigging with regular pipe inspection programs to determine the ideal cleaning intervals. Inspection data helps assess sediment rates, internal corrosion, and flow resistance — all of which can inform a more targeted pigging schedule.
Why Municipal Water Mains Get Clogged — and Why Cleaning Matters (new section)
Municipal water mains are critical to supplying clean water to homes, schools, businesses, and hospitals — but over time, these pipelines can develop buildup that affects both water quality and flow.
So, what causes the clogging?
Even treated water can carry small particles like sand, silt, or rust from aging pipes. Over time, these particles settle along the inside of the mains, forming a layer of sediment. Add to this the potential for biofilm (a slimy bacterial layer) and mineral scale, and you get serious flow restriction.
Other causes of clogging include:
Corrosion flakes from older metal pipes
Residual construction debris from pipeline installations or repairs
Organic growth in low-flow sections of the system
If not addressed, these deposits can lead to:
Discolored or foul-smelling water
Reduced pressure and flow rates
Strain on pumping systems and valves
Higher long-term maintenance costs
That’s where pigging comes in.
Pigging provides a mechanical way to clear out these deposits without using chemicals or cutting into the pipe. It restores flow, improves water clarity, and extends the usable life of the system — all with minimal disruption.
Challenges in Pigging Municipal Water Mains
While pigging is an effective cleaning method, it’s not without challenges — especially in large-scale municipal systems. Older infrastructure, unknown pipe layouts, dead ends, and limited pig launching points can complicate the process. Flow must also be carefully managed to ensure the pig moves at the right speed and avoids stalling or damaging the system.
Understanding these challenges helps municipalities plan better, budget accurately, and choose the right pigging equipment and inspection techniques.
Get In Touch With American Pipeline Solutions To Discuss Your Pigging Needs
The pigging process is somewhat involved but is not challenging to complete if a professional team manages the pipeline cleaning project. Should you want to learn more about the pigging solutions available for municipal water mains, don’t hesitate to speak with the professionals at American Pipeline Solutions. We know the benefits and pigging processes and can advise you accordingly on the best pigging process for your needs. To speak with us, you can contact us here.
