Drainage use gets restricted — and you need to know exactly when. While the line is open or being replaced, you can't use toilets, showers, washing machines, or dishwashers without sending water into an incomplete system. Ask for the specific windows. Some methods restrict use for hours, some for a day, some intermittently over several days. A household of four needs different planning from a single occupant, and knowing the windows in advance is the difference between an inconvenience and a crisis. Worth arranging: somewhere to be during the longest window, and — for a multi-day job — an honest conversation about whether you can comfortably stay in the property.
There will be an open excavation, and it needs to be safe overnight. Trenches are deeper than people expect and they don't get filled at the end of every day. Ask what happens overnight: barriers, covers, or plating, and how the site is secured. This matters most in properties with children or pets, and it's a reasonable thing to require rather than hope for. Keep everyone away from the edge. Excavated ground is unstable, and spoil piles are heavier and less stable than they look.
Machinery, spoil, and access. Excavation means equipment reaching the work area and material coming out of it — and that spoil has to sit somewhere until it goes back in. Ask where the machinery will come in and where the spoil will be stored. Frequently it's the driveway, which affects parking for the duration. Also worth confirming: whether any planting, fencing, or structures need moving first, and whose job that is.
The surface afterward, and what's actually included. This is where the widest gap between quotes hides. "Backfilled and levelled," "turf replaced," and "driveway restored" are three very different prices. Ask every bidder exactly what your property will look like when they leave. Concrete and paving rarely match after a patch, and landscaping is usually excluded unless it's specifically written in.
Neighbours, shared access, and easements. If the line crosses a shared driveway, runs near a boundary, or requires access across someone else's ground, that's a conversation to have early rather than on the morning the excavator arrives. And if work extends into the street or footpath, expect municipal requirements, possible traffic management, and notice periods.
Permits and inspection set the timeline. Sewer work is permitted, inspected work in essentially every jurisdiction. Replacement almost always requires a permit; many repairs do too. Underground utility locating happens before any excavation — gas, electricity, water, and communications share that ground. Which means the start date is frequently determined by the permitting process rather than by the plumbing. Ask for the realistic timeline, not the working time.