SewerOwner

Exclusions and assumptions

Every sewer price rests on assumptions, because nobody can see the whole job before starting it. That is not a defect in the industry; it is the nature of buried work.

What distinguishes a good proposal is not the absence of assumptions but whether they are written down and what happens when one is wrong.

What this page cannot establish

  • SewerOwner cannot tell you whether an assumption is reasonable for your property
  • SewerOwner cannot predict what will be found once work begins
  • an assumption being stated does not make it correct

Assumptions that commonly carry a sewer price

  • the material of the existing pipe
  • the depth of the line, particularly toward the connection
  • the length of the run being addressed
  • the diameter of the existing pipe
  • ground conditions and whether groundwater will be encountered
  • the absence of obstructions along the route
  • the position of other buried services
  • that the condition observed is the only one present
  • that access and working space will be as expected

Questions about each assumption that matters

  • Is this assumption written into the proposal, or is it understood?
  • How was it established — observed, inferred, or assumed?
  • What happens to the price if it turns out to be different?
  • Is there a stated limit on how much the price can move?
  • Would I be told before additional cost is incurred, or afterwards?
  • What would it cost to establish this before work starts rather than during?

Exclusions are different from assumptions

An exclusion says something will not be done. An assumption says something is expected to be true. A proposal can be silent on both, and silence is where disputes come from.

Restoration is the most common place this bites: a proposal that neither includes nor excludes replacing a driveway has not addressed the largest visible consequence of the work.

What would change the answer

  • the assumptions section of each proposal, however briefly stated
  • what the inspection actually established about the line
  • whether a locate has been performed

What to do next

An assumption only matters through the mechanism that applies when it turns out to be wrong.

Check the change-order process in writing

If your situation is different

Related, and why