If you or someone you care for has a urinary catheter, you will likely need a urine leg bag and a night drainage bag. The short answer:
- Leg bag (day): a small, drainable bag, usually 250 to 1000 mL, strapped to the thigh or calf so you can move around.
- Night bag: a larger bag, usually 2000 mL, hung beside the bed while you sleep. Many people link it to the bottom of the leg bag at bedtime.
Urine leg bag vs night drainage bag: what each one does
Both bags collect urine from an indwelling (Foley) catheter, a suprapubic catheter or an external (condom) catheter. They differ in size, where they sit and when you use them.
| Feature | Leg bag (day) | Night drainage bag |
|---|---|---|
| Typical capacity | 250–1000 mL (9–34 oz) | 2000 mL, sometimes 4000 mL |
| Where it sits | Strapped to the thigh or calf, under clothing | Hung on the bed frame or a stand, below the mattress |
| When you use it | Daytime, when you are up and about | Overnight, or during long rests in bed |
| How it is held | Elastic straps or a fabric holder | Hanger holes or hooks |
| Outlet | Lever, clamp, twist, flip valve or cap | Drain tap at the bottom (drainable bags) |
| Back-flow protection | Anti-reflux valve on most bags | Anti-reflux valve or tower on many bags |
Urine leg bag sizes: 250 mL to 1000 mL
Leg bags are labelled in millilitres (mL) and ounces (oz); one ounce is about 30 mL. Here is how common leg bags compare with night bags.
- Small (250–500 mL): flatter and easier to hide under trousers or a skirt. The Coloplast Conveen Active (250 mL) wraps around the thigh with the bag facing inward, which suits active people, and Conveen Security+ comes in 500 mL. You will empty these more often.
- Medium (540–750 mL): the everyday middle ground, including Hollister 540 mL, Bard Dispoz-a-Bag 19 oz, Conveen Contour 600 mL and Conveen Security+ 750 mL bags.
- Large (900–1000 mL): fewer trips to empty on long days and outings, but heavier when full. Examples include Hollister 900 mL and Bard Dispoz-a-Bag 32 oz bags.
Tubing length: a thigh bag needs a short tube and a calf bag a longer one, and the tube should reach without tugging on the catheter. Sterile or non-sterile: product titles say which, and some clinics ask for one or the other. Urine leg bags for men are the same bags women use; what changes is the catheter they connect to.
Bard Dispoz-a-Bag leg bags in 19 and 32 oz, straps included
Outlet taps and anti-reflux valves explained
The outlet, or tap, at the bottom is the part you handle most. Pick one you can open easily, especially if you have arthritis or a weaker grip.
- Lever tap: a small lever you push open and closed. Conveen Security+ comes with a lever outlet option.
- Clamp tap: a clamp closure that makes it easy to see whether the outlet is shut. Found on Conveen Security+ and Contour bags.
- Twist or rotary tap: turn to open, turn back to close.
- Flip-Flo valve: the flip-open drain on some Bard Dispoz-a-Bag leg bags; other Dispoz-a-Bags use a rubber cap outlet.
An anti-reflux valve is a one-way valve near the inlet that helps stop urine in the bag from flowing back up the tubing. Most leg bags have one, and many 2000 mL night bags have an anti-reflux tower at the top. Hollister also makes vented leg bag systems; Hollister says the vent helps prevent air building up, so the bag sits flatter.
Straps vs fabric leg bag holders
A full 750 mL bag weighs about 0.75 kg (1.7 lb), so good support matters for comfort and to keep the bag from pulling on the catheter.
- Elastic straps come with most leg bags. Hollister's instructions say to wear the ribbed side of the strap against the skin, not to overtighten, to check the skin under the straps regularly, and not to attach the bag at the knee. Spare straps are sold separately.
- Fabric leg bag holders (sleeves) slip over the thigh or calf and hold the bag in a pocket. Some people find them more comfortable and more secure. They are sized by leg circumference, so measure where the bag will sit and check the size range. Our urinary leg bag holder comes in small, medium and large for the upper leg, with lower-leg versions too.
- Latex: some bags, such as one Bard 32 oz Dispoz-a-Bag, come with latex straps. If the wearer or a caregiver has a latex allergy, choose straps or a holder labelled latex-free.
How to hook up a catheter bag (and link a night bag)
Always follow the instructions in the box and the routine your nurse showed you. Care teams teach two methods:
- Linking: the NHS has you connect the night bag to the bottom of the leg bag, so the leg bag stays on the catheter overnight.
- Switching: this BC patient information sheet has you disconnect the leg bag and attach the night bag to the catheter instead.
The general steps for linking:
- Wash your hands with soap and water before you start, and again when you finish.
- Empty the leg bag into the toilet and close the tap.
- Remove the cap from the night bag connector without touching the tip.
- Push the connector firmly into the leg bag outlet, then open the leg bag tap so urine can flow through.
- Hang the night bag on the bed frame or a stand, below the level of the bladder and off the floor. Check that the tubing has no kinks and that you are not lying on it.
- In the morning, close the leg bag tap first, then disconnect the night bag and empty it. Discard it, or rinse and cap it, as the manufacturer directs.
Hollister urinary leg bag instructions (quick version)
From Hollister's instructions for use:
- Measure the extension tubing so it reaches the leg bag without tugging, and trim the excess with scissors.
- Attach the free end to the connector at the top of the leg bag, and check for kinks.
- Fit the straps with the ribbed side against the skin, on the thigh or calf (never the knee). Do not overtighten.
- Empty the bag through the drain valve at the bottom.
- Non-sterile bags: between uses, empty, rinse with lukewarm water and hang to dry away from heat. Sterile bags: do not reuse.
Hollister leg bags and systems with trim-to-fit extension tubing
Night drainage bags: 2000 mL and 4000 mL
A standard night bag holds 2000 mL (68 oz), which is enough for most people overnight. Larger 4000 mL bags suit people who drain a lot or rest in bed for long stretches. When you compare urinary drainage bags, look for:
- Drainable or single-use: drainable bags have a tap at the bottom. The NHS notes that single-use night bags are usually used to reduce the risk of infection. Follow the manufacturer and your nurse on whether a bag can be reused.
- An anti-reflux valve or tower at the inlet.
- Tubing long enough to reach from the bed to the hanger without stretching.
- A way to hang it: most night bags have hanger holes for the bed frame or a stand. A clean plastic pail under the bag keeps it off the floor and catches drips.
2000 mL night drainage bags for overnight use
Emptying, cleaning and when to replace
- Empty before it is full. The NHS suggests emptying at about half to three-quarters full, and the BC sheet suggests every three to four hours or when half full. A heavy bag pulls on the catheter.
- Keep the outlet clean. Do not let the tap touch the toilet. If you touch the opening, wipe it with an alcohol swab.
- Replace on schedule. The NHS advises changing leg bags every 7 days; your clinic may set a different routine. Replace any bag that is damaged, stained or leaking.
If urine stops draining, first check for kinks and that the bag sits below the bladder. Go to the nearest emergency department if little or no urine drains for 4 hours or more and your bladder feels full, or if you have a fever over 38.5°C, chills, vomiting, blood clots or pus. Contact your nurse or doctor right away if urine looks cloudy, bloody or strong-smelling, or leaks around the catheter. If you are unsure, call 811 (Health811 in Ontario). This article is general information, not medical advice.
What to buy: a simple checklist
- Leg bags in the size and outlet you like, such as the Bard and Hollister bags above, or Coloplast Conveen.
- Night bags: one per night if they are single-use, or as directed.
- Spare straps or a fabric holder, because elastic stretches out over time.
- Extension tubing if the bag sits on the calf.
- Alcohol swabs for the connections.
Caring for a parent at home? Our home medical supplies checklist covers bed protection, skin care and more.
FAQ
Can you sleep with a urine leg bag?
For a short nap, often yes. Empty it first, keep the bag below your waist, and make sure you are not lying on the tubing. Overnight, a leg bag can fill up, and it can be pulled or squashed when you roll over. That is why most people add a 2000 mL night bag at bedtime. Ask your nurse what suits your catheter.
How do you empty a Bard catheter bag?
It depends on the outlet. Over the toilet, point the outlet down. On a Dispoz-a-Bag leg bag with a Flip-Flo valve, flip the valve open to drain, then flip it closed. On one with a rubber cap, pull the cap off, drain, then replace it. Do not let the outlet touch the toilet, and wipe it after. Bard night drainage bags drain from the outlet at the bottom; follow the leaflet in the box.
What sizes do urine leg bags come in?
Most range from 250 mL (9 oz) to 1000 mL (34 oz). Common sizes are 500, 540, 600, 750 and 900 mL. Night bags are usually 2000 mL.
How do you wear a urinary drainage bag?
Wear a leg bag on the thigh or calf, never at the knee, with the tubing free of kinks and the bag below the bladder. Use straps or a fabric holder that feels secure but not tight. At night, hang the larger bag on the bed frame or a stand.
Ready to restock?
Leg bags, night bags and straps are everyday supplies, so it helps to keep a spare week on hand. Orders are processed in 1–2 business days and typically arrive in 2–7 business days across Canada, in a plain, unmarked box with tracking emailed. Opened personal-care products cannot be returned, so check the size and outlet before you open a package. See our shipping and returns page for details.
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