For the purpose of this division, the following definitions shall apply unless the context clearly indicates or requires a different meaning:
Auxiliary water supply.Any water supply on or available to the premises other than the city’s approved public water supply. These auxiliary waters may include water from another purveyor’s public potable water supply or any natural source(s) such as a well, spring, river, stream, harbor, and the like, or used waters or industrial fluids. These waters may be contaminated or polluted or they may be objectionable and constitute an unacceptable water source over which the water purveyor does not have sanitary control.
Backflow.The reversal of the normal flow of water caused by either backpressure or backsiphonage.
Backflow prevention assembly.A device or means designed to prevent backflow.
(1) Air gap.The unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture, or other device and the flood level rim of said vessel. An approved air gap shall be at least double the diameter of the supply pipe, measured vertically, above the top of the overflow rim of the vessel, and in no case less than one inch.
(2) Reduced pressure principle device.An assembly of two independently acting approved checkvalves together with a hydraulically operating, mechanically independent pressure relief valve located between the checkvalves and at a point below the first checkvalve. The unit shall include properly located test cocks and tightly closing shutoff valves at each end of the assembly. The entire assembly shall meet the design and performance specifications as determined by a laboratory and a field evaluation program resulting in an approval by a recognized and approved testing agency for backflow prevention assemblies. The assembly shall operate to maintain the pressure in the zone between the two checkvalves at an acceptable level less than the pressure on the public water supply side of the device. At cessation of normal flow, the pressure between the two checkvalves shall be less than the pressure on the public water supply side of the device. In case of leakage of either of the checkvalves, the differential relief valve shall operate to maintain the reduced pressure in the zone between the checkvalves by discharging to the atmosphere. When the inlet pressure is two pounds per square inch or less, the relief valve shall open to the atmosphere. To be approved, these devices must be readily accessible for in-line testing and maintenance and be installed in a location where no part of the device will be submerged.
Backpressure.The flow of water or other liquids, mixtures, or substances under pressure into the distribution pipes of a potable water supply system from any source other than the intended source.
Backsiphonage.The flow of water or other liquids, mixtures, or substances into the distribution pipes of a potable water supply system from any source other than its intended source caused by the sudden reduction of pressure in the potable water supply system.
Double checkvalve assembly.An assembly of two independently operating approved checkvalves with tightly closing shutoff valves on each end of the checkvalves, plus properly located test cocks for the testing of each checkvalve. The entire assembly shall meet the design and performance specifications as determined by a laboratory and field evaluation program resulting in an approval by a recognized and approved testing agency for backflow prevention assemblies. To be approved, these devices must be readily accessible for in-line testing and maintenance.
Contamination.An impairment of the quality of the potable water by sewage, industrial fluids or waste liquids, compounds, or other materials to a degree which creates an actual potential hazard to the public health through poisoning or through the spread of disease.
Cross-connection.Any physical connection or arrangement of piping or fixtures between two otherwise separate piping systems, one of which contains potable water and the other nonpotable water or industrial fluids of questionable safety, through which or because of which backflow may occur into the potable water system. This would include any temporary connections, such as swing connections, removable sections, four-way plug valves, spools, dummy sections of pipe, or swivel or changeover devices or sliding multi-port tubes.
Cross-connection, control by containment.The installation of an approved backflow prevention device at the water service connection to any customer’s premises where it is physically and economically not feasible to find and permanently eliminate or control all actual or potential cross-connections within the customer’s water system, or the installation of an approved backflow prevention device on the service line leading to and supplying a portion of a customer’s water system where there are actual or potential cross-connections which cannot be effectively eliminated or controlled at the point of the cross-connection.
Cross-connection, controlled.A connection between a potable water system and nonpotable water system with an approved backflow prevention device properly installed and maintained so that it will continuously afford the protection commensurate with the degree of hazard.
Hazard, degree of.The term is derived from an evaluation of the potential risk to public health and the adverse effect of the hazard upon the potable water system.
(1) Health hazard.Any condition, device, or practice in the water supply system and its operation which could create or, in the judgment of the building official or plumbing inspector, may create a danger to the health and well-being of the water consumer.
(2) Plumbing hazard.A plumbing type cross-connection in a consumer’s potable water system that has not been properly protected by an approved air gap or approved backflow prevention device.
(3) Pollution hazard.An actual or potential threat to the physical properties of the water system or to the potability of the public or consumer’s potable water system, which would constitute a nuisance, be aesthetically objectionable, or could cause damage to the system or its appurtenances, but would not necessarily be dangerous to health.
(4) System hazard.An actual or potential threat of severe damage to the physical properties of the public potable water system or the consumer’s potable water system or of a pollution or contamination which would have a protracted effect on the quality of the potable water in the system.
Industrial fluids system.Any system containing a fluid or solution which may be chemically, biologically, or otherwise contaminated or polluted in a form or concentration such as would constitute a health, system, pollution, or plumbing hazard if introduced into an approved water supply. This may include but not be limited to: polluted or contaminated water; all types of process waters and used waters originating from the public potable water system which may have deteriorated in sanitary quality; chemicals in fluid form; plating acids and alkalies; circulating cooling waters connected to an open cooling tower and/or cooling towers that are chemically or biologically treated or stabilized with toxic substances; contaminated natural waters such as from wells, springs, streams, rivers, irrigation canals, or systems and the like; and oils, gases, glycerin, paraffins, caustic and acid solutions and other liquid and gaseous fluids used in industrial or other purposes or for firefighting purposes.
Pollution.The presence of any foreign substance (organic, inorganic, or biological) in water which tends to degrade its quality so as to constitute a hazard or impair the usefulness or quality of the water to a degree which does not create an actual hazard to the public health but which does adversely and unreasonably affect such waters of domestic use.
TCEQ.The state commission on environmental quality.
Water, nonpotable.Water which is not safe for human consumption or which is of questionable potability.
Water, potable.Any water which, according to recognized standards, is safe for human consumption.
Water service connection.The terminal end of the service connection from the public potable water system, that is, where the city loses jurisdiction and sanitary control over the water at its point of delivery to the customer’s water system. If a meter is installed at the end of the service connection, then the service connection shall mean the downstream end of the meter. There should be no unprotected takeoffs from the service line ahead of any meter or backflow prevention device located at the point of delivery to the customer’s water system. “Service connection” shall also include water service connection from a fire hydrant and all other temporary or emergency water service connections from the public potable water system.
Water, used.Any water supplied by a water purveyor from a public potable water system to a consumer’s water system after it has passed through the point of delivery and is no longer under sanitary control of the water purveyor.
(2002 Code, sec. 52.101)