Cross Connection Control
Purpose and Scope:
Public health officials have long been concerned about cross-connections and backflow connections in plumbing systems and in public drinking water supply distribution systems.  Such cross-connections, which make possible the contamination of potable water, are ever-present dangers. One example of what can happen is an epidemic that occurred in Chicago in 1933. Old, defective, and improperly designed plumbing and fixtures permitted the contamination of drinking water.  As a result, 1,409 persons contracted amebic dysentery; there were 98 deaths. This epidemic, and others resulting from contamination introduced into a water supply through improper plumbing, made clear the responsibility of public health officials and water purveyors for exercising control over public water, distribution systems and all plumbing systems connected to them. This responsibility includes advising and instructing plumbing installers in the recognition and elimination of cross-connections.

Cross-connections are the links through which it is possible for contaminating materials to enter a potable water supply. The contaminant enters the potable water system when the pressure of the polluted source exceeds the pressure of the potable source. The action may be called backsiponage or backflow. Essentially, it is reversal of the hydraulic gradient that can be produced by a variety of circumstances.

It might be assumed that steps for detecting and eliminated cross-connections would be elementary and obvious.  Actually, cross-connections may appear in many subtle forms and in unsuspected places.  Reversal of pressure in the water may be freakish and unpredictable. The probability of contamination of drinking water through a cross-connection occurring within a single plumbing system, may see remote; but, considering the multitude of similar systems, the probability is great. 

Cross connections amendment
The New York State Health Department requires that any property with an underground sprinkler system be equipped with a backflow device to protect public drinking water from possible contamination in the event of a sudden drop in water pressure. Our previous backflow regulations required the installation of a double check valve for backflow protection from residential sprinkler systems. The Nassau County Department of Health requires that a certified backflow tester test this device annually and forward the results to the MLWD.

In order to help our customers comply with this requirement, the MLWD has amended its Rules and Regulations to allow the installation of a pressure vacuum breaker as an acceptable backflow device on the branch line serving a sprinkler. The installation of a pressure vacuum breaker eliminates the annual testing requirement. Please note that all systems must be registered with the District regardless of which device is installed for backflow prevention. Your sprinkler company should be able to bring your system into compliance. For more information or to register your system, please contact Marshall Brandt at 466-4416. The District will be conducting a survey for unregistered underground sprinkler systems. Non-compliance with the ordinance subjects violators to penalty charges and/or an interruption of service.

The MLWD requires backflow prevention devices on all new services and on all existing services with underground sprinklers attached. The NCDOH requires annual testing of these devices. THE CUSTOMER IS RESPONSIBLE FOR TESTING THE DEVICE.

Completed backflow tests can be submitted via email to

Paul J. Schrader's Letter to the Editor

Manhasset Press
132 East Second Street
Minneola, NY 11501

Re: Cross-Connection Program

Dear Editor:

The Manhasset-Lakeville Water District has received a copy of Harold Michelsï¿¿ letter regarding our cross-connection control program and would like to set the record straight. 


On March 14, 2003 the notice of a public hearing on this issue was published in the four local newspapers including the Manhasset Press. On March 24, 2003 the public hearing was held and a decision reserved by the Board of Commissioners. The Commissioners waited on their decision to allow the announcement of this Rule change in our Annual Statement, mailed to all customers in May of 2003. The new Rules were officially adopted on July 16, 2003. 


The Health Department requires the District to discontinue water service for customers not in compliance. The District would have been remiss not to mention the ordinance in our notice to consumers. The Districtï¿¿s ultimate enforcement for compliance with our Rules and Regulations is the termination of service. This practice is consistent with town law, which allows water districts to cut off the water supply of violators of our rules and regulations Please note that the termination of service is not taken lightly by the District and would only occur after due process and as a last resort. Customers who call or write for extensions will find the District very receptive.


The decision to shift the burden to the homeowner was not taken lightly. Here are several key issues that prompted the final decision. Backflow devices are part of a homeownerï¿¿s plumbing system. In order to test the device the surrounding plumbing has to be in working order. This was forcing District personnel to become more and more involved with interior plumbing. Since District employees are not licensed plumbers, the Board cannot accept the liability associated with interior plumbing work. In addition, municipal law prohibits a public benefit corporation from working on private property. As these plumbing systems grow older, more and more work will be required to keep them operational. 

Currently 23% of our residential services maintain backflow devices. While all residential services installed after 1975 were required to install a backflow prevention devices, the majority were installed as part of underground irrigation systems. It is unfair for the majority of our customers to bear the cost for testing devices which they donï¿¿t even own.

Finally, the District is not meeting the annual requirements set forth by the Health Department for testing devices. The District has tried unsuccessfully to use additional personnel and overtime to meet these requirements. Almost all other Districts in the County require the homeowner to complete the test. With appropriate enforcement, this change will allow us to satisfy the County requirements.

Very truly yours,

Paul J. Schrader, P.E.