Sewer blockages are a major cause of sewer flooding. In England and Wales for example, blockages cause more than 4,000 property flooding incidents each year. In North America, such incidents of sewer blockages total several hundred thousand each year. In Australia and New Zealand, these add up to thousands. The practice usually used to clear sewer blockages is by employing 1,500 to 2,000 psi (10.3 to 13.8 MPa) water jetting. The first few units of equipment with 3,000 to 30,000 psi (20.6 to 206 MPa) capability, however, are being trialed to clean drains and remove any blockages and sediments. There has been a long standing concern that high pressure water jets may cause damage to the network of drains and sewers. This conclusion flows from the decades of water cutting of concrete, steel and other high strength materials. Whether damage is caused or not depends on the condition of the sewer main. Contractors just blasting the water jets into a main, typically made of concrete has resulted in failures that required sewer agency's forces to respond on an emergency basis. Therefore, before one can evaluate the merits of high pressure low volume jetting machines over low pressure high volume type, the intended users have to understand the overall landscape of sewer cleaning and maintenance across America. Given there are 56,000 sewer agencies in America alone, the author embarked on a survey of a large representative sample of these sewer agencies, cleaning companies, engineering firms, and manufacturers. With the help of Great Southern Press, this survey expanded to reaching out globally to over 10,000 of stakeholders. Oildom publishing and Benjamin Media offered additional assistance. The objectives of this paper are to share a) the results of the responses to the fifteen questions from the survey b) the lessons learnt c) the outcome of a preliminary assessment of ultra high pressure jetters versus machines that have been in use for the past few decades and d) conclusions drawn that would lead toward more effective means and methods.
