(a) 
General standards.
No water connection from a public drinking water supply system shall be made to any establishment where an actual or potential contamination or system hazard exists without an air gap separation between the drinking water supply and the source of potential contamination. The containment air gap is sometimes impractical and, instead, reliance must be placed on individual "internal" air gaps or mechanical backflow prevention devices. Under these conditions, additional protection shall be required at the meter in the form of a backflow prevention device (in accordance with AWWA Standards C510 and C511, and AWWA Manual M14) on those establishments handling substances deleterious or hazardous to the public health. The city need not require backflow protection at the water service entrance if an adequate cross connection control program is in effect that includes an annual inspection and testing by a certified backflow prevention device tester. It will be the responsibility of the city to ensure that these requirements are met. It is the water customer's responsibility to coordinate and pay for any required annual inspections.
(b) 
Cross connections prohibited.
No water connection from any public drinking water supply system shall be made to any condensing, cooling, or industrial process or any other system of nonpotable usage over which the public water supply system officials do not have sanitary control, unless the said connection is made in accordance with the requirements of subsection (a) of this section. Water from such systems cannot be returned to the potable water supply.
(c) 
Overhead bulk water dispensing stations.
Overhead bulk water dispensing stations must be provided with an air gap between the filling outlet hose and the receiving tank to protect against back siphonage and cross-contamination.
(d) 
Backflow prevention devices.
The use of a backflow prevention device at the service connection shall be considered as additional backflow protection and shall not negate the use of backflow protection on internal hazards as outlined and enforced by local plumbing codes.
(Code 1975, § 23-109)
All backflow prevention assemblies shall be tested upon installation by a recognized backflow prevention assembly tester and certified to be operating within the specifications. Backflow prevention assemblies which are installed to provide protection against high health hazards must also be tested and certified to be operating within specifications at least annually by a recognized backflow prevention device tester. The water customer will coordinate and pay for these annual tests. The city will be notified prior to the annual tests being conducted so they can be present when they are run.
(Code 1975, § 23-110)
(a) 
Qualification of testers; categories.
Recognized testers shall have completed a commission approved course on cross connection control and backflow prevention and pass an examination administered by the TNRCC or its designated agent. The accredited tester classification shall be broken down into two categories:
(1) 
The general tester is qualified to test and repair backflow prevention assemblies on any domestic, commercial, industrial or irrigation service except firelines.
(2) 
The fireline tester is qualified to test and repair backflow prevention assemblies on firelines only. The state fire marshal office requires that a person performing maintenance on firelines must be employed by an approved fireline contractor.
(b) 
Accreditation for proof of prior course completion.
Individuals that can show proof of completion of a course and passage of an exam based on the ABPA or ASSE national exam, prior to the effective date of the ordinance from which this article is derived, may be recognized as accredited for the term of their current certification (not to exceed three years).
(Code 1975, § 23-111)
Gauges used in the testing of backflow prevention assemblies shall be tested for accuracy annually in accordance with the University of Southern California's Foundation of Cross Connection Control and Hydraulic Research and/or the American Water Works Association Manual of Cross Connection Control (Manual M-14). Testers shall include test gauge serial numbers on test and maintenance report forms.
(Code 1975, § 23-112)
A backflow prevention assembly test and maintenance report must be completed by the recognized backflow prevention assembly tester for each assembly tested. The signed and dated original must be submitted to the city water department for record keeping purposes. Should the tester choose to use a report format which differs from that found in this section, it must minimally contain all information required by the report form. Test and maintenance reports shall be retained for a minimum of three years. The public water supplier must provide these records to commission staff for inspection upon request.
(Code 1975, § 23-113)