Cross-Connection Control Manual Office of Water (4606M) EPA 816-R-03-002 www.epa.gov/safewater February 2003 Printed on Recycled Paper Cross-Connection Control Manual United States Environmental Protection Agency Office of Water Office of Ground Water and Drinking Water First Printing 1973 Reprinted 1974, 1975 Revised 1989 Reprinted 1995 Technical Corrections 2003 Preface lumbing cross-connections, indirectly in water supply cross-connection control from Pwhich are defined as actual distribution systems. It is both the basic hydraulic or potential connections intended to be used for educa- concepts through the inclusion between a potable and non- tional, administrative, and of a sample program that can potable water supply, constitute technical reference in conduct- be a guide for a program at the a serious public health hazard. ing cross-connection control municipal level. New backflow There are numerous, well- programs. This manual is a devices have been included in documented cases where cross- revision of an earlier book this revision that are now being connections have been respon- entitled Water Supply and produced by manufacturers sible for contamination of Plumbing Cross-Connections (PHS reflecting the needs of the drinking water, and have Publication Number 957), market. Updated actual cross- resulted in the spread of disease. which was produced under the connection case histories have The problem is a dynamic one, direction of Floyd B. Taylor by been added containing graphic because piping systems are Marvin T. Skodje, who wrote schematic illustrations showing continually being installed, the text and designed the how the incidents occurred and altered, or extended. illustrations. how cross-connection control Control of cross-connec- Many of the original practices could be applied to tions is possible, but only illustrations and text have been eliminate future re-occurrence. through thorough knowledge retained in this edition. Previ- A more detailed explanation of and vigilance. Education is ous revisions were done by cross-connection control essential, for even those who are Peter C. Karalekas, Jr. with “containment” practice has experienced in piping installa- guidance from Roger D. Lee been included together with the tions fail to recognize cross- incorporating suggestions made use for “internal backflow connection possibilities and by the staff of the EPA Water protective devices” and “fixture dangers. All municipalities with Supply Division, other govern- outlet protection”. public water supply systems mental agencies, and interested This 1989 edition was should have cross-connection individuals. prepared by Howard D. control programs. Those This 3rd edition was Hendrickson, PE, vice president responsible for institutional or produced as a result of an of Water Service Consultants, private water supplies should updated need for cross- with assistance from Peter C. also be familiar with the connection control reference Karalekas, Jr. of Region 1, EPA, dangers of cross-connections material reflecting an increase Boston. and should exercise careful in cross-connection control This latest (2003) edition surveillance of their systems. activity throughout the United has technical corrections This Cross-Connection Control States. It has been revised and provided by Howard D. Manual has been designed as a re-issued reflecting a demand Hendrickson, P.E., showing tool for health officials, water- for its use, together with updates on pages iv, 18, 23, 30, works personnel, plumbers, and requests for a document that 31, and 32. any others involved directly or covers the broad spectrum of ii • CROSS-CONNECTION CONTROL MANUAL Contents American Water Works Association Policy on Cross-Connections . iv 11 Valved connection between potable water and sanitary sewer . 15 12 Air gap . 16 Chapter 13 Air gap in a piping system . 16 1. Purpose & Scope . 1 14 Barometric loop . 17 2. Public Health Significance of Cross-Connections . 2 15 Atmospheric vacuum breaker . 17 3. Theory of Backflow and Backsiphonage . 12 16 Atmospheric vacuum breaker typical installation . 17 4. Methods and Devices for the Prevention of Backflow and 17 Atmospheric vacuum breaker in plumbing supply system . 17 Backsiphonage . 16 18 Hose bibb vacuum breaker . 18 5. Testing Procedures for Backflow Preventers . 25 19 Typical installation of hose bibb vacuum breaker . 18 6. Administration of a Cross-Connection Control Program . 30 20 Pressure vacuum breaker . 18 7. Cross-Connection Control Ordinance Provisions . 33 21 Typical agricultural and industrial application of pressure vacuum breaker . 19 Appendixes 22 Double check valve with atmospheric vent . 19 A. Partial list of plumbing hazards . 38 23 Residential use of double check with atmospheric vent . 19 B. Illustrations of backsiphonage . 38 24 Double check valve . 19 C. Illustrations of backflow . 40 25 Double check valve detector check . 20 D. Illustrations of air gaps . 41 26 Residential dual check . 20 E. Illustrations of vacuum breakers . 41 27 Residential installation . 20 F. Glossary . 42 28 Copper horn . 20 G. Bibliography . 43 29a Reduced pressure zone backflow preventer . 21 H. Sample cross-connection survey form . 44 29b Reduced pressure zone backflow preventer . 21 I. Sample cross-connection test form . 45 30 Reduced pressure zone backflow preventer principle of operation . 22 31 Plating plant installation . 22 Illustrations 32 Car wash installation . 22 Human blood in the water system . 2 33 Typical by-pass configuration, reduced pressure principle devices . 23 Burned in the shower . 3 34 Typical installation, reduced pressure principle device, Heating system anti-freeze into potable water . 3 horizontal illustration . 23 Salty drinks . 4 35 Typical installation, reduced pressure principle device, Paraquat in the water system . 4 vertical installation . 23 Propane gas in the water mains . 5 36 Typical installation, double check valve, horizontal and vertical Chlordane and heptachlor at the Housing Authority . 5 installation . 24 Boiler water enters high school drinking water . 6 37 Typical installation, residential dual check with straight Pesticide in drinking water . 6 set and copper horn . 24 Car wash water in the water main . 7 38 Pressure vacuum breaker . 26 Shipyard backflow contamination . 7 39 Reduced pressure principle backflow preventer, Step 1 . 27 Chlordane in the water main . 8 40 Reduced pressure principle backflow preventer, Step 2 . 27 Hexavalent chromium in drinking water . 8 41 Double check valve assemblies, Method 1 . 28 Employee health problems due to cross-connection . 9 42 Double check valve assemblies, Method 2 . 29 Dialysis machine contamination . 10 43 Cross-connection protection, commercial, industrial and residential . 30 Creosote in the water mains . 11 44 Backsiphonage, Case 1 . 38 Kool aid laced with chlordane . 11 45 Backsiphonage, Case 2 . 38 46 Backsiphonage, Case 3 . 39 Figure 47 Backsiphonage, Case 4 . 39 1 Pressure exerted by one foot of water at sea level . 12 48 Backsiphonage, Case 5 . 39 2 Pressure exerted by two feet of water at sea level . 13 49 Backsiphonage, Case 6 . 39 3 Pressure on the free surface of a liquid at sea level . 13 50 Backflow Case 1 . 40 4 Effect of evacuating air from a column . 13 51 Backflow Case 2 . 40 5 Pressure relationships in a continuous fluid system at 52 Backflow Case 3 . 40 the same elevation . 13 53 Backflow Case 4 . 40 6 Pressure relationships in a continuous fluid system at 54 Air gap to sewer subject to backpressure—force main . 41 different elevations . ..