Are there clear design criteria for construction of maintenance chambers in sewage lines ? For eg:  domestic sewage line of 6" pipe line and 9" pipeline will need which type of chamber construction in terms of height, from ground, height w.r.t. road level and with consideration of reverse flow into to domestic homes in the event of chamber blockage? The current situation I am facing is described below:

BWSSB tookup the relaying of 9" sewage line from its old 6" line, owing to frequen blockage at the chamber and causing reverse flow into low lying houses. The old line were 50-60 years old and our houses were built to old chamber top level reference, so that reverse back flow will not over flow over the toilet floors. During 5 decades, and advent of new technology asphalting, the road level has gone up by 1-1.5 feet. New during recent relaying of 9" pipe line, new chambers are being built and are raised to new road level, at times 1 foot above the road level. This results in our old houses built in 50s, to go below the new chamber level. Accidental blockage of chambers will result in back flow as in line with the chamber water level. My efforts of last 5 decades to raise my toilet level above the chamber top water level is severely affected by the new chamber top water line.

My suggestion is that new chamber top water line cannot be raised to the new road level, just because the asphalting has built up and the chamber top has to align to the road top surface. The solution is to maintain the old chamber level with one lid, build up the chamber height by 1-2 feet with a ring and make a second lid so as to match to the top level of chamber. Is this plausible?

What are my options for seeking help / action in this matter?

Shama Sundar Kathavate
shyam.kathavate@gmail.com