If you are going to be doing any type of construction or repairs that will require you dig into the ground, you need to be sure that you will not disrupt any buried utilities. Most municipalities have some type of "Call Before You Dig" service, such as Miss Utility or Call 811 to find where the major, municipal utilities are located on your property. However, this is not always enough. There are a few different private utility lines that may cause a problem for you. Here are a few examples.
The utility company may not know where you buried the electric lines from your house to the shed, garage, or pool in the yard. If the new wiring was something you did, hopefully, you made some type of mark or map to let you know where it is. However, if it was done by a previous owner, you probably have no idea where the wires run under the ground. You will need to hire a professional utility locating company to be safe. You would not want someone to be electrocuted when pushing a metal digging tool into underground electrical wires.
The city may not keep track of every new septic system that is installed. While it is mandatory in some cities to file a permit that shows the location of any new tank on the property, many people choose to forgo this process to save some money. You would not want to have an area of the yard dug up for your new pool to find out the septic system was just ripped out. In addition, if you have an irrigation system for your yard you need to know where it is before you just start digging. While it is easy enough to shut off the system to avoid a flood, you could end up damaging the system.
There may be an underground propane or gas line going from your home to an outbuilding, an outdoor cooking area, or to the pool heating system that utility company does not know about. Hitting one of these lines could cause an explosion that is very dangerous and may even be deadly.
Even if you are going to plant a tree in the yard, you need to know exactly where any underground utilities are. Contact the city's utility locating service a few days before you plan to start digging and hire a professional company to come check the area out too. While the pros are there, you can have them make a map of your yard that indicates where everything is so you do not have to worry about it again, or until you have a new line installed for something else.