A hose can leak for any number of reasons, but the first thing to check is how tight the connection is. Make sure the fitting is securely attached, but avoid overtightening, which can damage threads or washers. If that doesn’t work, try wrapping thread tape around the male threads to create a tighter seal and prevent leaks. If there is still a leak, check again for cracks or debris in the threads, as they can prevent a tight seal.