Even if you know you don't have to worry about contaminants, unstable soil, or environmental risks, you still need to know if there are pipes and utility lines underground. If your dig is anywhere near civilization, there's always a chance there are some mains located below the surface.
Call Before You Dig!
You've probably seen the phrase "Call before you dig!" plastered all over the place. It's the slogan for the national 811 number you call to connect with those that can mark underground utility mains for you.
Not only is locating these mains of the utmost importance, it's also the law. Although, the law varies state by state, it's still a necessity you take this step no matter where you are in the country. Hitting any kind of utility line can have disastrous consequences.
Besides, it's usually a free, or cheap service. But there's a few gaps in its efficiency. You see, when the line-locating contractor comes out to mark the lines, he or she works mainly from a map. These services do use locator tools, but their utility maps are notorious for being off, or outdated. That's where the gaps come in.
The line locator contractor will only know to mark the things that match up between what's on the map and what the location device detects. In addition, the locator tool in use isn't always of the highest quality. In fact, some can only detect certain frequencies or certain materials. Finally, it's not on the line locator contractor to seek out those lines that are not a part of a public utility.
Hire a Private Contractor
Not all lines are held by public utility companies. There are many private lines, forgotten lines, and lines that go deeper than some contractors can detect. It's technically okay for you to start digging after the utility lines receive their markings, but it's still not safe for you to do so. You will need to hire a private utility location specialist, preferably a geotechnical drilling contractor (such as one from Haz-Tech Drilling Inc.).
These services use ground-penetrating radar (GPR). This method employs electromagnetic radiation to build a three-dimensional image of what's underground. This represents one of the best ways you can avoid the hazards associated with hitting an unknown line.
It's best to pay the cost of due diligence than to pay for a costly mistake. Call the 811 or local utility services connection, but don't forget to do your own independent survey as well. It's not enough to think it's safe to start digging. You have to know it's safe.