Common rules for grave digging include keeping at least 3 feet of room between graves, digging a level grave of the appropriate size and digging the grave to the correct depth. For casket burials, there should be at least 18 inches of dirt on top of the casket, so a casket 30 inches in height requires a 4-foot grave. If only the body is being buried, it should have at least 2 feet of dirt on top of it.
To check for other graves in the area before digging, the grave digger shoves a poker into the ground. If the poker touches a grave, the grave digger finds the edge and then measures 3 feet from that edge.
The standard grave size for an adult is 3 feet by 8 feet, as of 2015. The standard grave size for a child is 3 feet by 5 feet, although this isn't always the case. When burying ashes, the standard grave size is 1 foot by 1 foot, but this may vary depending on the size of the urn. Grave sizes may also vary depending on the cemetery and the buyer, as cemeteries sometimes allow buyers to purchase larger or smaller graves.
Graves must meet the minimum depth to prevent the casket or body from reaching the surface if soil erodes, and to prevent any diseases from spreading. The standard grave depth was 6 feet during the Black Plague, but this law changed later.