Not so flushed

Maintenance

We're having an issue with a 1950/60's bungalow sewer pipe, which only has a VERY slight gradient to the manhole - which itself is under next-doors raised patio!

The issue has been compounded recently as the tenant replaced the resplendent plum toilet for a white one, which of course has a much smaller cistern.

As the original cistern would have been around 9-12 litres, and the current ones for sale are usually 4/6 litres on a dual flush, we are getting repeated blockages which have to be jetted clear.

Does anyone know if it is possible to still source a larger cistern, or does the Law now insist that 6 litres is the maximum size allowable?

The clay sewer pipe from the house to the manhole was jetted and camera'd last week and shows it to be in fairly good condition, no breakages although each joint would provide a little resistance which may just be enough to start a blockage with the slope being so slight. The jetter suggested that it could be sleeved to make a smoother passage which may help - but no guarantees, and of course this comes at a cost, though less than replacing the entire pipe. This is the 3rd blockage in the last 6 months, and no wipes or ST's found, just paper and usual waste.

Has anyone else come across a similar circumstance, and how did you manage to solve it?