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Starting at $33.20
WCOPP Series Sanitary Watertight Cap with 3 or 4 Bolt Holes – UV Resistant Molded Plastic
SKU WCOP404P
Starting at $34.50
Starting at $146.00
Starting at $84.00
Starting at $30.00
Starting at $45.00
WS Series Cast Iron Well Seal – Single Drop Pipe with Split Top Plate, Cable Tapping & Vent
SKU WS400100
Starting at $33.00
Starting at $27.50
WCB Series Sanitary Watertight Cap with Conduit Tapping and Vent – Secure Well Cap Solution
SKU WCB400
Starting at $140.00
WS Series Well Seal – Heavy-Duty Watertight Sealing for Submersible Pump Installations
SKU WS625100S
Starting at $129.00
Starting at $300.00
Starting at $160.00
Starting at $272.00
MERRILL WELL CAPS & WELL SEALS
Compare Well Caps & Well Seals
Well cap: Your water pipe exits underground through a pitless adapter or unit.
Well seal: Your water pipe comes out the top of the well. Exposed piping needs protection from freezing.
Replacing an existing one? Match your current setup.
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| Compare Products | ||||||||||||||
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| Why Choose It? | Premium cast iron with stainless hardware. | Heavy-duty cast iron construction. | Sanitary cast iron for 6-inch wells. | Corrosion-resistant aluminum. | Fits special 5-inch casing. | Aluminum strength with less weight. | Faster installation at a lower cost. | Tough, impact-resistant plastic. | Economical cast iron cover. | Lightweight and economical. | Lightweight and economical. | Proven durability with a split top. | Proven durability with a split top. | Solid steel plate construction. |
| Best For | Maximum wellhead protection. | Larger conduit and vent connections. | Everyday Pitless installations with pitless adapters. | Outdoor installations where rust is a concern. | Replacements where the casing measures 5" OD casing. | A lightweight metal-top cap for 4- or 5-inch wells. | Economical sanitary protection for 4- or 5-inch wells. | A plastic cap for demanding outdoor use. | Vented applications that do not require a watertight cap. | One pipe through the well seal. | Two pipes through the well seal. | One pipe; split design for easier installation. | Two pipes; split design for easier installation. | Single-pipe setups, including larger pipe sizes. |
| Casing Fit & Sizes | Measure outside diameter (OD)3"* / 4" → 4-1/2" 5" → 5-9/16" 6" → 6-5/8" 8" → 8-5/8" *Confirm the 3" WC300 fit. |
Measure outside diameter (OD)4" → 4-1/2" 5" → 5-9/16" 6" → 6-5/8" 8" → 8-5/8" 10" → 10-3/4" |
Measure outside diameter (OD)6" → 6-5/8" | Measure outside diameter (OD)4" → 4-1/2" 5" → 5-9/16" 6" → 6-5/8" |
Measure outside diameter (OD)5" → 5-1/2" Special 5-1/2" OD fit. |
Measure outside diameter (OD)4" → 4-1/2" 5" → 5-9/16" |
Measure outside diameter (OD)4" → 4-1/2" 5" → 5-9/16" |
Measure outside diameter (OD)4" → 4-1/2" 6" → 6-5/8" |
Measure outside diameter (OD)5-5/8" to 6-1/4" One cap fits this range. |
Measure inside diameter (ID)2" · 3" · 4" · 4-1/2" · 5" · 6" · 6-1/4" · 8" Not for SDR17 casing. |
Measure inside diameter (ID)4" · 4-1/2" · 5" · 6" · 6-1/4" Not for SDR17 casing. |
Measure inside diameter (ID)4" · 5" · 5-5/8" · 6" · 6-1/4" · 8" · 10" · 12" | Measure inside diameter (ID)4" · 5" · 6" · 6-1/4" | Measure inside diameter (ID)4-1/2" · 5-5/8" · 6" · 6-1/4" · 8" · 10" |
| Sealing & Protection | Sanitary watertight design; two neoprene O-rings. | Sanitary watertight design; wide neoprene compression gasket. | Sanitary watertight design; compression gasket and screened vent. | Sanitary watertight design; gasket seal and stainless steel screen. | Sanitary watertight design with bronze-screened ventilation. | Sanitary watertight design; neoprene gasket/O-ring and stainless steel screen. | Sanitary watertight design; gasket sealing and stainless vent screen. | Sanitary watertight, vermin-resistant design; neoprene seals. | Protective vent cap; specification does not list a sanitary watertight rating. | Compression packer seals inside the casing and around the matched pipe opening. | Compression packer seals inside the casing and around both pipe openings. | 3/4" rubber compression packer seals inside the casing. | 3/4" rubber compression packer seals inside the casing. | 3/4" rubber compression packer seals inside the casing. |
| Materials & Hardware | Painted cast iron body and rings; stainless steel bolts. | Painted cast iron; zinc-plated bolts and nuts. | Painted cast iron; neoprene seals; zinc-plated bolts; bronze vent screen. | Cast aluminum body; acorn nuts protect exposed threads. | Cast aluminum top; PVC bottom ring; zinc-plated hex bolts. | Aluminum top; PVC base; stainless steel cap screws; acorn nuts cover threads. | UV-resistant plastic top; PVC base; acorn nuts cover exposed threads. | High-impact ABS body; stainless and plated hardware, by component. | Painted heavy cast iron. | Molded ABS plates; extra-thick rubber packer; zinc-plated bolts and washers. | Molded ABS plates; zinc-plated bolts, nuts and washers. | Painted cast iron top/bottom plates; zinc-plated bolts. | Painted cast iron top/bottom plates; zinc-plated bolts. | Painted steel top/bottom plates; zinc-plated bolts and washers. |
| Pipe, Wiring & Vent Connections | Conduit: 1"-1-1/2". Vent: 1/2"-1", by model. Screened vent ell included. | Conduit: 1-1/2" or 3". Vent: 1"-2-1/2", by model. | 1" conduit; 3/8" diameter vent. Top-tap and grounding variants available. | 1" conduit; 1/2" or 3/4" vent. Optional top tapping, ground screw and terminal lugs. | 1" conduit; 3/4" vent. Grounding and conduit-adapter variants available. | 1" conduit; 1/2" or 3/4" vent. Top-tap and grounding variants available. | 1" conduit; 1/2" or 5/8" vent. Grounding variants available. | 1-1/4" IPS conduit; 7/16" vent. | 3/4" conduit size. | Single pipe: 1"-3" options; blank options. Cable/vent openings vary; 2" model has neither. | 1-1/4" × 1" drop-pipe openings; 1/2" vent tapping. | Single pipe: selected 1"-5" sizes. Cable and vent tapping vary by model. | 1-1/4" × 1" or 1-1/4" × 1-1/4" pipe openings, by model; 1/2" vent tapping. | Single pipe: selected 1"-4" sizes. Cable: 3/4"-1-1/4"; vent: 1/2" or 3/4", by model. |
| Installation & Service | Bolted cover and separate clamping ring. Stainless bolts resist corrosion. | Bolted cover with gasket and clamping ring. | Bolted cover and clamping ring. Select the required top-tap or grounding variant. | Removable bolted cover. Match the standard, top-tapped or grounding configuration. | Bolted aluminum cover over a PVC base. Check the conduit-adapter option. | Removable cover; acorn nuts protect threads during outdoor exposure. | Extra wrench clearance; O-ring retains cap bolts. Match the three- or four-bolt design. | Select the exact casing fit and follow the model's fastening instructions. | Four hex-head cap screws secure the cap to the casing. | Solid top plate. Match pipe opening and casing ID before selecting a size. | Solid top plate. Confirm both pipe sizes and their arrangement. | Split top plate simplifies installation around the pipe. | Split top plate; match both pipe openings to the existing arrangement. | Solid top plate. Choose the exact casing/pipe combination; sizes are not interchangeable. |
Check Your Measurements: OD = outside diameter; ID = inside diameter. For caps, match actual casing OD; for seals, match actual casing ID and pipe openings. Nominal pipe size alone does not confirm fit. Casing material and wall thickness also matter.