Merrill 4″ Well Seal Cap – ABS Sanitary for 4″ Casing
$59.99 on Amazon.com (as of October 17, 2026, 12:57 PM EST) View details ↗
The Merrill MFG 4″ Double Drop Well Seal Cap is a durable, sanitary solution designed for residential and farm water well systems. Engineered for use with 4″ inside diameter well casing, this heavy-duty seal features 1-1/4″ x 1″ drop pipe openings to ensure a secure, watertight fit. The thick rubber gasket provides an effective barrier against contaminants, while the molded PVC construction resists corrosion and extends product life in harsh environments.
Installation is straightforward thanks to retaining nuts that allow for quick and secure attachment—ideal for maintenance or repairs. The 1/2″ female NPT threads accommodate standard vent pipes, making integration seamless. Whether you're sealing a new well or upgrading an existing system, this well seal cap delivers reliable performance and long-lasting protection for your water supply.
| Well Casing Compatibility | 4″ inside diameter |
|---|---|
| Drop Pipe Openings | 1-1/4″ x 1″ |
| Material | Molded PVC plastic |
| Gasket Material | Thick rubber |
| Vent Pipe Thread | 1/2″ female NPT |
| Load Capacity | Secure retaining nuts for easy installation/removal |






