Maintenance & Reliability · SOP

Commercial Facility Winterization And Hose Bib Drain Down

Procedure to drain, purge, and protect all exterior hose bibs and associated water supply lines in commercial buildings prior to freezing temperatures. Prevents pipe bursts, structural water damage, and costly spring repairs.

Estimated Time

45 min

Difficulty

Intermediate

Regulation

CSA B480

Version

1.0

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Purpose

This SOP ensures that all exterior hose bibs and their supply lines are completely drained of standing water and treated with antifreeze before the onset of sub‑freezing weather. By isolating the water source, venting pressure, and physically removing residual water, the risk of ice expansion cracking pipes and fittings is eliminated. Proper winterization also extends the service life of hose bib seals, backflow preventers, and wall penetration sleeves.

Scope

Applies to all exterior hose bibs (frost‑free and standard), wall‑mounted service valves, irrigation tie‑ins, and auxiliary water outlets on commercial, institutional, and multi‑tenant facilities. Includes supply lines routed through unheated crawlspaces, basements, parking garages, and mechanical chases. Does not cover internal plumbing systems, fire sprinkler lines, or domestic hot water recirculation loops — those require separate shut‑down procedures.

Safety Precautions

LOTOLock out the main building water supply or the dedicated zone valve before removing any hose bib or drain plug. Verify zero flow by opening a downstream fixture.
PPEWear ANSI Z87.1 safety glasses, cut‑resistant gloves, and slip‑resistant boots. Propylene glycol antifreeze is non‑toxic but can cause floor slipperiness; contain spills immediately.
SLIPWater and glycol mixtures create slick surfaces. Use absorbent mats or spill pads at each work area. Keep a dry vacuum on hand for spot cleanup.
TEMPIf the ambient temperature during the procedure is below 0°C (32°F), water may freeze before draining is complete. Work in warmer periods or use a portable heater to keep the area above freezing.

Required Tools & Materials

Adjustable wrench (10" or 12") and flat‑head screwdriver
Bucket or drain pan (minimum 5 gal capacity)
Wet/dry shop vacuum with crevice tool
Propylene glycol antifreeze (non‑toxic, potable‑water safe; e.g., RV antifreeze)
Foam insulating covers specific to hose bib size
Teflon tape (PTFE thread seal tape)
Pipe insulation foam sleeves (self‑sealing, R‑3.5 or higher)
Marker and weatherproof label tags
Flashlight or work light
Absorbent spill pads

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Procedure: Step-by-Step

1 Isolate the water supply. Locate the dedicated isolation valve (ball valve or gate valve) for each exterior hose bib. Turn the valve completely clockwise to shut off water. Open the hose bib for 3–5 seconds to verify no flow; close it again.

2 Relieve line pressure and drain main volume. Open the exterior hose bib fully. If the bib is below grade or in a pit, attach a short length of garden hose to direct water into a bucket. Let gravity drain until flow reduces to a trickle.

3 Open low‑point drain/bleed plug. Inside the facility, locate the low‑point drain or bleeder valve on the supply line (typically the lowest fitting in the run, often in a crawlspace). Open this drain and capture any remaining water in a pan. Leave open until water stops flowing.

4 Vacuum‑assist residual water. Using the shop vacuum, insert the hose into the open hose bib and apply suction for a minimum of 30 seconds. Move the vacuum hose around the bib opening to remove water trapped in the valve body and horizontal pipe drops. A clear airflow from the low‑point drain confirms the line is dry.

5 Remove and inspect accessories. Unscrew any garden hoses, Y‑splitters, vacuum breakers, or backflow preventers from the bib. Inspect the rubber washer and seat for cuts or deformation. Replace washer if necessary. Wrap the bib threads with fresh Teflon tape (2–3 wraps clockwise) to prepare for reinstallation next season.

6 Add non‑toxic antifreeze. Pour approximately 50 mL (1.7 fl oz) of propylene glycol antifreeze directly into the open hose bib. For frost‑free bibs, tilt the bib downward slightly to let the antifreeze run into the valve stem cavity. Alternatively, inject antifreeze through the low‑point drain using a squeeze bottle.

7 Close and insulate the hose bib. Close the exterior hose bib hand‑tight only — do not use tools, as overtightening can crack the valve body. Place the foam insulating cover over the bib, ensuring the closed end fits snugly against the wall. Secure with a zip tie or Velcro strap if the cover includes one.

8 Insulate supply line and tag. Slit foam pipe sleeves lengthwise and snap them around any exposed sections of the supply line in unheated spaces. Seal longitudinal joints with foil tape. Attach a bright weatherproof label to each bib noting: “WINTERIZED — DO NOT USE — Isolate via [valve location] on [date]”. This tag prevents accidental operation during cold weather.

Commercial Facility Winterization And Hose Bib Drain Down

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