Building over a sewer or lateral drain
Self-certified agreement criteria
1. I confirm the diameter of the public sewer/lateral drain is 150mm/6inches or less
2. I’ve verified the location and depth of the public sewer/lateral drain I intend to build over
3. I understand the liability for any damage/operational issues to the public sewer/lateral
drain caused by my building works, rests with me
4. I’m not aware of any easements or restrictive covenants which would prohibit building
work over or close to the public sewer/lateral drain
5. I confirm the public sewer/lateral drain is not made from pitch fibre (instead it’s made
from clay, plastic or concrete)
6. I confirm the public sewer/lateral drain is gravity-based foul, surface water or combined
(and is not a pressurised/rising main)
7. I confirm the depth of the pipe from the existing ground level to the bottom of the pipe
(invert) is less than 2000mm
8. I confirm the that the pipe is at least 500mm from the external face of my building
9. I confirm there are no internal manholes or inspection chambers within the footprint of
my proposed building
10. I confirm that no manhole will be added, removed or relocated
11. I confirm that my proposed structure will not require building over more than 6 metres of
the public sewer/lateral drain
12. I confirm the extension will utilise strip/trench fill foundations that will be a depth greater,
or equal to the invert of the sewer (piled or raft foundations require a full build over
agreement).
13. I confirm there will be at least 150mm horizonal clearance from the public sewer/lateral
drain to the floor slab or the edge of the foundations, and will be protected in line with
H4 (Building Regulations 2010) and Thames Water specifications