§ 25-85. Backflow prevention methods and devices.

(a)

Any irrigation system that is connected to the potable water supply must be connected through a backflow prevention method certified by the Texas Commission on Environmental Quality (TCEQ). The minimum standard for the city shall be a double check value [valve] assembly, if there are no conditions that present a health hazard. The backflow prevention device must comply with the International Plumbing Code and/or the Uniform Plumbing Code and must be approved certified by the American Society of Sanitary Engineers (ASSE); or the Foundation for Cross-Connection Control and Hydraulic Research, University of Southern California; or International Code Council-Evaluation Service (ICC-ES); or the International Association of Plumbing and Mechanical Officials—Research and Testing (IAPMO R&T) the Uniform Plumbing Code; or any other laboratory certifying agencies that has equivalent capabilities for both the laboratory and field evaluation of backflow prevention assemblies. The backflow prevention device must be installed in accordance with the laboratory approval standards or if the approval does not include specific installation information, the manufacturer's current published recommendations.

(b)

If conditions that present a health hazard exist, one of the following methods must be used to prevent backflow:

(1)

An air gap may be used if:

a.

There is an unobstructed physical separation; and

b.

The distance from the lowest point of the water supply outlet to the flood rim of the fixture or assembly into which the outlet discharges is at least one inch or twice the diameter of the water supply outlet, whichever is greater?

(2)

Reduced pressure principle backflow prevention assemblies may be used if:

a.

The device is installed at a minimum of twelve (12) inches above ground in a location that will ensure that the assembly will not be submerged; and

b.

Drainage is provided for any water that may be discharged through the assembly relief valve.

(3)

Pressure vacuum breakers may be used if:

a.

No back-pressure condition will occur; and

b.

The device is installed at a minimum of twelve (12) inches above any downstream piping and the highest downstream opening. Pop-up sprinklers are measured from the retracted position from the top of the sprinkler.

(4)

Atmospheric vacuum breakers may be used if:

a.

No back-pressure will be present;

b.

There are no shutoff valves downstream from the atmospheric vacuum breaker;

c.

The device is installed at a minimum of six (6) inches above any downstream piping and the highest downstream opening. Pop-up sprinklers are measured from the retracted position from the top of the sprinkler;

d.

There is no continuous pressure on the supply side of the atmospheric vacuum breaker for more than twelve (12) hours in any twenty-four-hour period; and

e.

A separate atmospheric vacuum breaker is installed on the discharge side of each irrigation control valve, between the valve and all the emission devices that the valve controls.

(c)

Backflow prevention devices used in applications designated as health hazards must be tested upon installation and annually thereafter.

(d)

If there are no conditions that present a health hazard, double check valve backflow prevention assemblies shall be used to prevent backflow if the device is tested upon installation and test cocks are used for testing only.

(e)

If a double check valve is installed below ground:

(1)

Test cocks must be plugged, except when the double check valve is being tested;

(2)

Test cock plugs must be threaded, watertight, and made of nonferrous material;

(3)

A y-type strainer is installed on the inlet side of the double check valve;

(4)

There must be a clearance between any fill material and the bottom of the double check valve to allow space for testing and repair; and

(5)

There must be space on the side of the double check valve to test and repair the double check valve.

(f)

If an existing irrigation system without a backflow-prevention assembly requires major maintenance, alteration, repair, or service, the system must be connected to the potable water supply through an approved, properly installed backflow prevention method before any major maintenance, alteration, repair, or service is performed.

(g)

If an irrigation system is connected to a potable water supply through a double check valve, pressure vacuum breaker, or reduced pressure principle backflow assembly and includes an automatic master valve on the system, the automatic master valve must be installed on the discharge side of the backflow prevention assembly.

(h)

The irrigator shall ensure the backflow prevention device is tested by a licensed backflow prevention assembly tester prior to being placed in service and the test results provided to the local water purveyor and the irrigation system's owner or owner's representative within ten business days of testing of the backflow prevention device

(Ord. No. 2010-O-026, § 2(F), 3-1-10)