A leg bag is a small, flat pouch that straps to your thigh or calf and collects urine from a catheter. It’s designed to be worn under clothing during the day, giving you the freedom to move around without carrying a visible drainage container. Most leg bags hold about 500 milliliters (roughly 2 cups) of urine and connect to either an indwelling catheter or an external catheter via a short length of tubing.
How a Leg Bag Works
The bag itself is typically made of vinyl or another lightweight material. A tube at the top connects to the end of your catheter, and urine flows down by gravity into the bag. At the bottom, a small drainage port with a twist valve lets you empty the bag into a toilet without disconnecting anything.
Most leg bags include an anti-reflux valve, which is a one-way mechanism that prevents urine from flowing backward through the tubing and into the bladder. This matters because backflow increases the risk of urinary tract infections. Two flexible straps, usually elastic or fabric, hold the bag in place against your leg.
Where to Wear It
You can strap a leg bag to either your thigh or your lower leg, depending on comfort and what type of clothing you’re wearing. The key rule is that the bag must stay below the level of your bladder at all times so gravity can do its job. If the bag sits higher than your hip, urine can flow backward into the tubing.
Thigh placement works well under looser pants or skirts. Calf placement is more discreet under fitted trousers and keeps the bag farther from the catheter insertion site, which some people find more comfortable. Either position is fine as long as the tubing isn’t kinked or pulling.
Leg Bags vs. Bedside Drainage Bags
Many people who use a leg bag during the day switch to a larger bedside drainage bag at night. The nighttime bag holds significantly more urine, so you don’t have to wake up to empty it. You simply disconnect the leg bag before bed, attach the larger bag, and hang it from the side of your bed frame (again, keeping it below bladder level).
You might hear the term “Foley bag” used interchangeably with leg bag. A Foley catheter is the name for the entire drainage system, including the thin tube inserted into the bladder, the drainage port, and whatever bag is attached. The leg bag is just one size option within that system.
Emptying and Cleaning
Because leg bags are relatively small, they fill up faster than bedside bags. You should empty yours when it’s about one-third to one-half full. Waiting longer adds weight that can pull on the catheter and also increases pressure that could force urine backward past the valve. For most people, this means emptying the bag every few hours during the day.
To empty it, you open the twist valve at the bottom over a toilet or measuring container, let the urine drain out completely, then close the valve. Wash your hands before and after. Keeping the drainage port clean and avoiding contact between the valve tip and the toilet helps reduce infection risk.
Replace your leg bag with a new one once a week, according to guidance from Memorial Sloan Kettering Cancer Center. Even with regular cleaning, bacteria can build up inside the bag and tubing over time.
Skin Irritation and Comfort
The most common complaint with leg bags is skin irritation from the straps. A study comparing two leg bag designs found that patients frequently reported dermatitis, blisters, and general discomfort, particularly with latex-based products. When researchers tested a nonlatex, cloth-backed bag against a standard latex model in 30 men recovering from prostate surgery, there was a clear preference for the cloth-backed version. Only one case of minor skin irritation occurred in the entire study, and it involved the latex bag.
Features that made the biggest difference in comfort included cloth backing against the skin, elastic or fabric straps instead of rubber, flexible tubing that didn’t kink easily, and a secure snap closure on the drainage port. If you’re experiencing redness, itching, or blistering under the straps, switching to a latex-free bag with fabric backing is a straightforward fix. You can also rotate the bag’s position slightly each day to avoid constant pressure on the same patch of skin.
Choosing the Right Leg Bag
Leg bags come in a few different capacities, but the standard adult size is around 500 milliliters. A smaller bag is less noticeable under clothing but needs to be emptied more often. A larger bag gives you more time between trips to the bathroom but adds bulk and weight on your leg.
When selecting a bag, pay attention to the strap material (cloth or fabric over latex if you have sensitive skin), whether it includes an anti-reflux valve, and the type of drainage port. Twist valves are the most common and tend to be reliable. Some bags also come with a flip-open tap, which can be easier to operate one-handed. Your catheter supplier or home health nurse can help match the bag’s connector size to your specific catheter tubing.