How do you check utility detection underbidding risks in Qardho?

A low bid for utility detection in Qardho usually means the survey was never priced as survey work. Cable locators, tracing, markout, trial pits, standby time and record drawings drop out of the total, so the digger starts with no plan of what lies under the plot. Ask two contractors to write out exactly what they will scan, how, and what they will hand over.

What does an unrealistically low utility detection bid leave out?

It leaves out the hidden cost items, not the visible ones. A realistic allowance covers a desk study of existing records, a site walkover, electromagnetic locating for metallic or energised lines, a sonde or tracer for non-metallic pipe such as plastic water main, markout on the ground in paint or pegs, a small number of hand-dug trial pits to confirm depths, standby time while the machine waits, and as-built records handed to the client.

Each of those is a separate task with its own labour and equipment. When the total is squeezed, the cheapest items survive and the slow ones disappear. Some methods also have limits: a locator traces what it can energise or detect, and a plastic or concrete pipe with no tracer wire may not respond. The bidder should say which lines can be found and which cannot, and what will be done about the ones that cannot.

Why do omitted costs turn into damage to buried services?

Damage happens when a machine cuts ground that nobody marked. If detection was priced out or rushed, the excavator works on guesswork from a general plan or from what the previous site happened to show. A strike on a water main floods the trench and undermines the sides. A strike on a power cable puts the operator and the crew at risk and can take the whole site off supply. A strike on a telecom duct is cheap to hit and slow to repair.

Where trench walls are loose or sandy, escaping water can slump them, so the consequences go beyond the first break. Confirm the actual soil and water table against the project's site investigation rather than assuming a soil type. Repairs also cost time that no bid allowed for. Ask the municipal engineer's office and the water, power and telecom providers whether they hold any utility drawings for the plot. That is the question to settle before, not after, the first bucket goes in.

How do you detect underbidding before work starts?

Compare the written scope line by line, not the totals. Ask every bidder for the same schedule: records review, locating method, depth of markout, trial pits, standby, reinstatement and records. A bid that answers every line with a number is telling you something different from one that answers half of them.

• Ask for the names of the equipment and the operator's recent detection work, with a reference you can call.
• Ask for a marked plan and a scan record before excavation, not after.
• Ask what happens if a line is found that nobody expected: who stops the machine, who is called, and what the contract says about the change.
• Walk a recent site and look at how the markout was done, whether records were kept and who supervised the dig.

Keep the answers as documents attached to the tender. A verbal promise adds nothing to the file when the trench is open.

What to do next

Write the detection scope into the tender as a priced schedule with separate lines, then ask two contractors to price it and return their method statement and rate breakdown in writing. Before excavation, hold a short pre-dig meeting with the operator, the supervisor and the service providers, and record the markout plan and the stop-work rule in the site file.