Before you start to install your French drain, you should make sure all the utility lines on your property are marked. Some landscaping companies will handle this beforehand, but if they can’t, or you’re installing a French drain yourself, you should call 811 to have a professional come out and mark the utility lines. This step goes hand in hand with ensuring you have the proper permits and that your French drain is inspected soon after to save you a headache in the long run.