AWWA C509

Covers — iron-body resilient-seated gate valves for potable water supply, with NRS or OS&Y stems and mechanical-joint/flanged/push-on ends, including tapping gate valves, for a defined water temperature range.

Does NOT cover (exclusions) — the following are governed elsewhere:

• Rubber-seated butterfly valves for water → AWWA C504; larger/higher-pressure resilient gate valves → AWWA C515.
• Process metal-seated gate valves → API 600 / 603.
• The connecting pipe/fittings → AWWA C151 / C110.

C509 is the buried-water-main resilient gate valve; process gate valves follow the API standards.

C509 sets minimum requirements for resilient gate valves:

• Design — iron body, resilient (encapsulated) wedge, full-bore unobstructed seat, NRS/OS&Y stem.
• Materials & Coating — corrosion-protective interior/exterior (e.g., fusion-bonded epoxy).
• Ends — mechanical-joint, flanged, or push-on to the waterworks system.
• Testing — shell and seat (bubble-tight) testing at rated water pressure.

AWWA C509 is the standard resilient-seated gate valve for water distribution. Its rubber-encapsulated wedge seals against a smooth, full-bore seat with no bottom groove to trap grit, delivering reliable bubble-tight shutoff on buried mains. Non-rising stems suit buried installation, and iron bodies are protected with fusion-bonded epoxy.

It is distinct from metal-seated process gate valves (API 600) and from the higher-pressure/larger AWWA C515 resilient gate valve. Companion water valves include the C504 rubber-seated butterfly valve.

Engineering Note: Resilient-seated gate valves give tight, low-maintenance shutoff for water mains, but the resilient wedge and epoxy coating limit temperature and service — do not repurpose a C509 valve for hydrocarbon or high-temperature process duty.