11.10.230 Backflow prevention requirements.
(1) Requirement. All backflow prevention assemblies required herein shall be of a type and model approved by the Oregon State Human Resources Department, Health Division (OSHD), and shall be installed in accordance with OSHD requirements and the provisions of subsection (2) of this section.
(2) Installation. Backflow prevention assemblies shall be installed by a State-licensed installer, at customer’s expense, on each service line of the customer’s system at or near the property line or, if approved, immediately inside the building being served, but in all cases before the first branch line leading off the service line wherever any of the following conditions exist:
(a) Where there is an auxiliary water supply which is or can be connected to the potable water piping;
(b) Where there is piping for conveying fluids (liquids or gases) other than potable water and where that piping is installed and operated in a manner which could cause a cross-connection;
(c) Where there are intricate plumbing arrangements which make it impracticable to ascertain whether or not cross-connections exist;
(d) Where there has been a history of repeating the same or similar cross-connections, even though these have been removed or disconnected;
(e) Where there is a building over three stories in height or any plumbing system that is greater than or equal to 30 feet above the main from which it is served;
(f) Where there is backflow or back siphonage potential;
(g) Where the system is not open for inspection; or
(h) Where the system is subject to being submerged.
(3) Device Type. The type of protective assembly required under subsection (2) of this section shall be commensurate with the degree of hazard, which exists as follows.
(a) Air Gap or Reduced Pressure Assembly. An approved air gap of at least twice the inside diameter (but not less than one inch) of the incoming supply line measured vertically above the top rim of the vessel or an approved reduced pressure principle backflow prevention (RP) assembly shall be installed where the substance which could backflow is a contaminant or hazardous to health. Examples of premises where these conditions may exist include, but are not limited to, sewage treatment plants, pump stations, sewage piping, chemical manufacturing plants, hospitals, mortuaries, plating plants, car washes, medical clinics and auxiliary water systems.
(b) Double Check Valve or Double Detector Check Valve Assembly. An approved double check valve (DC) assembly or double detector check valve (DDC) assembly shall be installed where the substance which could backflow is a secondary contaminant or objectionable but does not pose an unreasonable risk to health.
(c) Pressure Vacuum Breaker or Atmospheric Vacuum Breaker. An approved pressure vacuum breaker or an atmospheric vacuum breaker shall be installed where the substance which could backflow is objectionable but does not pose an unreasonable risk to health, and where there is no possibility of back pressure in the downstream piping. A shutoff or control valve may be installed on the line downstream of a pressure vacuum breaker, but shall not be installed downstream of an atmospheric vacuum breaker.
(4) Locations. Examples of locations requiring backflow prevention assembly are listed below, but are not limited to:
(a) Irrigation Systems. In the case of irrigation systems, an approved atmospheric vacuum breaker or an approved pressure vacuum breaker may be authorized, provided no back pressure is possible and no chemical or material injection or mixing exists;
(b) Private Fire Protection Services. In the case of all private fire protection services, an approved backflow prevention assembly with a monitoring meter or detection system to detect unauthorized use or leakage within the system and a remote meter shall be required. The type of backflow prevention device shall be as follows.
(i) An approved double detector check valve assembly shall be required for low and medium hazards. Low and medium hazards are systems with or without pumper connection, but no auxiliary water supplies available, chemical or additives, detectable cross-connection and serving a building three stories or less.
(ii) An approved reduced pressure principle backflow prevention assembly and a single detector check shall be required for high hazards. High hazards are systems with auxiliary water supplies, chemical additives, detectable cross-connections or a building exceeding three stories.
(c) New Construction. Where adequate plans and specifications are not available and no realistic evaluation of the proposed water uses can be determined, the installation of maximum backflow protection may be required at the water service connection.
(5) Inspections and Leakage Tests. It shall be the duty of the assembly owner at any premises where backflow protective assemblies are installed to have thorough inspections and leakage tests made immediately upon installation of assemblies, when assemblies are moved and at least once a year, or more often in those instances where successive inspections indicate repeated failure. The frequency of these tests or the replacement of the assembly because of failure shall conform to State regulations. The inspections, tests, repairs and/or replacement of assemblies shall be at the expense of the assembly owner and shall be performed by an assembly tester who is licensed by the Oregon State Health Division. Test and repair or replacement shall be performed within 30 days from receipt of notice to test. The assembly owner is required to contact a tester who can perform the work in the necessary period. The assembly owner shall notify the utility a minimum of 48 hours in advance when the test is to be performed so that the utility may witness the tests if so desired. Records of such tests, repairs and overhaul shall be kept by the owner, and a copy submitted to the utility within 30 days of completed tests. (Ord. 68 § 1, passed 2-19-1991; Code 2014 § 50.23)