U dont need to filter the manhole water unless its determined it is toxic. And if that is the case then u better not pump it in the storm drains. Yes it is not a good idea to pull over and take a leak wherever u feel like it. The absorbing blankets are issued to every truck. I would hope that u would use it instead of letting your hydrolic fluid leak all over the place. It is a law that if u block a sidewalk that u need to provide a safe passage for pedistrians. Some places enforce it and some dont.
I deal with this stuff everyday and make out just fine. I wouldnt make it publicly known that u worked for expertec. Some of the worse work i have ever seen was done by that company. I just got done fixing one of their screw ups from a year ago.
We enjoy our clean water and air out here thats why we have these laws in our state. If u dont like it go back to wherever your from and pollute your own area