How frequently are sewer pipes inspected? 

How frequently are sewer pipes inspected?

How frequently are sewer pipes inspected?

There are over 11 billion meters (36 billion feet) of wastewater pipes that have been installed underground around the world, and this number continues to grow as the number of dwellings increases to support a growing population. A lot of these wastewater pipes have been installed in the last 40-70 years, and the pipes themselves come in a variety of materials and diameters.  

sewer pipe

The design life of a wastewater pipe?

Engineers design pipes for a certain design life, meaning the duration of time that the asset is expected to be in use before it deteriorates to the point of failure. In the case of underground wastewater pipes the design life is generally between 100 years and 150 years. During the pipes design life, it is prudent to check the pipes regularly to make sure that they are not blocked or broken.

sewer inspection with cctv camera

How frequently are these wastewater pipe inspections carried out?

This process is called an inspection and is usually carried out by trained professional using a small CCTV camera that is remotely driven through the pipe, capturing video footage of the internal condition of the pipe as it goes. The best practice is to undertake these inspections at a frequency of around once every 10 years, equivalent to inspecting 10% of the network every year. This frequency means that it would take the relevant water authority 10 years to get around to the same pipe if it were to continuously inspect their pipe network. Water authorities are inspecting their network continuously, but not at the ‘best practice’ frequency of once every 10 years. The frequency at which pipes are inspected differs based on the water authorities’ budgets and the risk of that asset’s failure to the community and environment. In some areas and countries, it is common for pipes to be assessed at a much lower frequency i.e. Inspected at less than 10% of the network every year. In the United States, almost 7% (source: of the network is inspected each year, but other countries like the United Kingdom and Australia (based on anecdotal industry experience) is less than 5%.  

How frequently are these wastewater pipe inspections carried out?

One way to increase the frequency of wastewater pipe inspections is to decrease the cost of the inspection itself. To decrease the cost of an inspection there must be an associated increase in productivity. This can come from new hardware, software, more effective training methods and materials, or by applying an improved process to inspections. Another way to increase the frequency of inspections is to increase the budget associated with carrying out inspections, however, this is a very challenging method since most water authorities are budget constrained and therefore have a limited ability to apply this method. 

About the Author

Amanda Siqueira is an Australian civil and environmental engineer who has worked in design, construction and remediation of drainage and sewer pipes in Australia, New Zealand and the UK. She has passion for all things pipes and is also one of the Co-founders of VAPAR.

Experience the future of pipe condition assessments.

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