This is in addition to building codes which must be met. Also, minimum lot sizes and separations must be met when wells and septic systems are used. In urban areas, sewers and water lines often provide service to households. There may also be restrictions based on covenants established by private parties such as the real estate developer. There may be easements for utilities to run water, sewage, electric power, or telephone lines through a lot. Something which is meant to improve the value or usefulness of a lot can be called an appurtenance to the lot. Structures such as buildings, driveways, pavements, patios or other surfaces, wells, septic systems, signs, and similar improvements which are considered permanently attached to the land in the lot are considered to be real property, usually part of the lot but often parts of a building, such as condominiums, are owned separately. Such structures owned by the lot owner(s), as well as easements which help the lot owners or users, can be considered appurtenances to the lot. A lot without such structures can be called a vacant lot, urban prairie, spare ground, an empty lot, or an unimproved or undeveloped lot. Many developers divide a large tract of land into lots as a subdivision. Certain areas of the land are dedicated (given to local government for permanent upkeep) as streets and sometimes alleys for transport and access to lots. Areas between the streets are divided up into lots to be sold to future owners. The layout of the lots is mapped on a plat diagram, which is recorded with the government, typically the county recorder's office. The blocks between streets and the individual lots in each block are given an identifier, usually a number or letter. Land originally granted by the government was commonly done by documents called land patents. Lots of land can be sold/bought by the owners or conveyed in other ways. Such conveyances are made by documents called deeds which should be recorded by the government, typically the county recorder's office. Deeds specify the lot by including a description such as one determined by the "metes and bounds" or quadrant methods, or referring to a lot number and block number in a recorded plat diagram. Deeds often mention that appurtenances to the lot are included in order to convey any structures and other improvements also. In front of many lots in urban areas, there are pavements, usually publicly owned. Beyond the pavement, there may sometimes be a strip of land called a road verge, and then the roadway, being the driveable part of the road.