This is a great question and fortunately it is not something we have not needed to address until the 2019 season.
First and foremost it is critical that your property has a locate equest filed with your local locating service. For us in Wisconsin that is Diggers Hotline. It is also important to document your contact at Diggers Hotline, the time and date you called in the request, the start date provided by diggers hotline and the ticket number.
There is typically a 3 business day window in which the locating services are given to mark any buried utilities per your locate request. We have never had an issue with utilities not being marked until the summer of 2019. This is not a good situation for anyone and can result in the delay of a project, damage to excavating equipment and most importantnly the injury to personel on the job site or even the loss of life.
When an unmarked utility is hit, dug up or exposed the first and most important thing is to remove everyone from the job site to a secure distance and prevent anyone from unknowingly entering the jobsite. Next contact Diggers Hotline with your ticket number and explain what happened and they will coordinate a crew to address the situation. Follow all recomendations provided by Diggers Hotline.
Needless to say the pool project will be shut down temporarily while the area is made safe and a game plan can be made to address the situation. Now you may be asking, are there going to be any additional costs of the project due to hitting the utility. The answer is yes. The total cost depends on the extent of the repair to the utility and whether or not the pool will need to be moved and how long the delay will be.
If the delay is longer than a few days your builder may have to postpone your project and move on to another in the meant time. If this happens there will likely be an additional mobilization fee to bring back the heavy equipment to complete the excavation of the pool.
Secondly there will likely be a need to move the pool to another portion of your property that is the proper distance from the discovered utilites. This can lead to filling in of the area that was already dug for the original placement of the pool, so there will also likely be additional cost to fill in the original hole. It may also cause issues with delivery of the pool shell. In some cases the pool shell delivery and the pool dig are scheduled for the same day so if the pool dig is put on hold the pool shell will still be delivered. The pool shell will need to be offloaded and temporarily stored on the jobsite until the pool can be dug in its new location. This will lead to your lawn dying in the location where the pool was stored. This will add additional cost to a project as well.
Ultimately all of the addtional cost to complete the pool project due to the unmarked utility is the responsibility of the homeowner. The property owner is the only person with legal standing to recoop these costs from the utility locating firm that was hired by Diggers Hotline to locate all of the utilities in the property.
The good news is that this rarely happens. Cooler heads always prevail in these situations and in the end there can always be a positive resolution. Be letigious with documenting the incident Whether it was an accident or oversight by the locating firm it is still not a good situation for anyone involved. That is why it is absolutely necessary that you do not dig until you call Diggers Hotline.