What is a Dry Hydrant and how does it work?

What is a dry hydrant and how does it work?

• A dry hydrant is a permanently installed, non-pressurized suction point that lets a fire engine draft from a static water source (pond, lake, stream, cistern) year-round.
• A hard-piped line runs from a screened intake under water to a pumper connection at the roadside. When the engine’s primer creates vacuum, water is lifted through the pipe to the pump.
• After use, the system drains back into the source, so it won’t freeze. There is no pressurized supply and usually no check/foot valve—free draining is key to cold-weather reliability.

Core Components (of a typical WFR-based build)

Intake Strainer (submerged)

• Purpose: keep debris, fish, and ice out; reduce vortexing and air entrainment.
• Guideline: position 1–2 ft above the bottom and at least 2 ft. below expected ice.

Suction Pipe

• Typically, 6 in. PVC (Schedule 40 or 80; 80 for added durability or long runs). Larger diameters can be used to reduce friction on very long runs. (WFR does not supply this.)
• The joints are solvent-welded couplings; use primer and cement rated for the pipe schedule and water temp.
• Layout: keep runs as short and straight as possible; long-radius fittings minimize loss.

Shore Elbow and Support

• Long-radius 90° elbow to turn the line up toward grade.
• Solid support/anchorage: concrete pad or thrust block, cribbing, stainless or galvanized straps/brackets to prevent movement and protect joints.
• Dry hydrant head/adapter at the roadside
• This is the pumper connection that the engine hooks to.
• WFR heads are available: 6 in. NH/NST (national hose) threads normally female swivel but male is available. Other NHT sizes are available.
• Storz (commonly 4 in. or 6 in)

Other adapters on request (cam-lock, etc.)

Includes a protective cap and chain. Confirm your department’s suction size and thread before ordering.

Drain/Bleeder

A small weep hole or a bleeder valve at the low point or near the head to admit air and allow the line to drain back after use (prevents freezing). Sized and placed so the system fully drains but doesn’t admit debris.

Protection and Identification

• Bollards or guard posts to protect the head from vehicles.
• Signage/ID plate and reflective marking so crews can find it quickly.

Recommended Options and Accessories

• Backflush connection: a valved port to reverse-flow and clean the strainer/pipe.
• Ice guard or perforated standpipe around the intake in northern climates.
• Wildlife/debris screen at shoreline entry.
• Hardware kit: stainless fasteners, anti-seize for aluminum threads, pipe straps.
• Approach pad at the truck connection for stable apparatus setup.

Site Selection and Hydraulic Basics

• Reliable Water: year-round source with adequate volume and depth. Keep the intake off the bottom and away from heavy silt or vegetation; locate in the deepest part available.
• Access: safe apparatus approach/turnaround in all seasons; firm ground; head height commonly set about 24–30 in. above grade for easy hard-suction connection.
• Suction Lift: keep total lift (vertical distance from water surface to pump intake) as low as practical. Most engines can draft up to ~20–25 ft. under ideal conditions, but performance and priming time improve if you keep it under ~15 ft.
• Friction Loss: use large-diameter pipe (6 in. minimum is common), minimize length and fittings, and use long-radius bends. For long runs, consider up-sizing to reduce loss.
• Freeze: bury pipe below frost depth and slope it back to the water so it drains completely after use.

Installation Overview

1. Plan and Permit

• Verify local codes and AHJ requirements (NFPA 1142 is a common reference).
• Obtain environmental/wetlands approvals if required.
• Confirm thread type/size with the fire department.

2. Lay Out the Run

• The straightest, shortest route from water to roadside, with continuous fall back to the water for drainage.
• Choose head location for truck access and protection.

3. Excavate and Bed

• Trench below frost line. Provide a stable gravel bed, especially at fittings and transitions.
• At the intake, prepare a pad/cribbing to hold the strainer elevation and resist settling.

4. Assemble the Intake and Pipe

• Solvent-weld pipe and fittings per manufacturer instructions.
• Install the WFR strainer, set to the target elevation and clearances.
• Add anchoring/ballast as needed to keep the intake oriented and off the bottom.

5. Install Shore Elbow and Head

•  Set the long-radius elbow and a solid support or concrete backing.
•  Mount the WFR head/adapter at the planned height and orientation; verify clearance for caps and hard-suction coupling.
•  Install the cap and chain.

6. Add Drainage/Bleeder

• Drill or plumb the weep/bleeder so the line fully drains. Protect openings with screens as needed.

7. Backfill and Protect

• Backfill with suitable material, compact carefully around pipe and fittings.
• Install bollards/guard posts and signage.

8. Test and Document

• Draft test with the department: verify priming time, flow, and no air leaks.
• Backflush to confirm clear flow. Record details for pre-plan maps.

Maintenance Tips

• Inspect the head, cap gasket, and threads at least annually; lubricate threads lightly with anti-seize.
• Backflush and draft test annually (and after major storms).
• Check intake elevation and remove silt or vegetation if needed.
• Confirm drain-back after use in freezing weather.

Typical Bill of Materials (varies by site)

• WFR intake strainer (barrel, ice/low-profile, or floating model)
• 6 in. PVC pipe (Sch 40 or 80) and solvent-weld couplings
• Long-radius 90° elbows (6 in.)
• WFR dry hydrant head/adapter with cap (choose 6 in. NH/NST, 5 or 6 in. Storz, etc.)
• Bleeder/vent (valve or weep)
• Anchorage/support: concrete, straps, hardware
• Bollards/guard posts and signage
• Optional: backflush valve/port, ice guard

Why Choose WFR

We stock WFR’s dry hydrant strainers, adapters, heads, and caps because they’re rugged, widely compatible with fire service threads, and supported with a full range of options. If you’re not sure which strainer or head style fits your apparatus and site, we can help you size and spec a complete kit.

Notes and Disclaimers

• Always follow local codes and the authority having jurisdiction. Environmental permits may be required for in-water work.
• Confirm thread type and size with your fire department before ordering.
• For long runs, unusual lifts, or high target flows, contact us—proper sizing of pipe diameter, fitting count, and strainer type makes a big difference in performance.