Sewer cleaning
"With modern technologies, Brisbane City Council is presently able to inspect approximately 80 kilometres of stormwater pipes every year, which means that on average the entire system will be inspected once every 30 to 40 years.”
Or more accurately, some stormwater pipes will be inspected every 5-10 years and the vast majority will never be looked at.
At current rates of housing development I'd be surprised if there was less than 80km of new stormwater pipes laid every year.