MUDs are encouraged to keep their wells operational for contingency, for backup, for peak water demands, and for emergency purposes. If a pipeline that brings surface water to a MUD needs repair, for example, the MUD may need to shift temporarily to well water so that the surface waterline can be shut down while it is under repair. Well water can also be used as a backup water supply if the City of Houston’s water system is temporarily out of service due to weather emergencies or maintenance requirements. Once the 2025 and 2035 mandated reductions are achieved, the MUDs will need their wells to be in good operating condition to provide the balance of water demand – 40% and 20% respectively.