Disadvantages of french drains
A French drain is difficult to detect because it consists in an underground pipe, that helps move water from one place to another. The pipe is covered either with rock or gravel. You will need a shovel to dig out the spot where the French drain is.
Survey the property
French drains are usually used to redirect water away from a home. The drain will always be located where there is a slope, so to find it, search out the areas of the property that are not flat.
Search under gravel
Because French drains are covered with gravel or rocks, look around for any area that contains it. Beds of gravel can hide a French drain underneath. You just need to dig and find out.
Search for the pipe
Find the end of the pipe. It will have one end exposed. Dig along the pipe to find out where it begins.
Search for signs of flooding
Search around the property after a rainy day. If you see that areas which were supposed to dry up get flooded you can then locate the French drain. This happens frequently because French drains are difficult to install right.