Thank you for contacting the Bureau of Utilities with your question. The cap you have sent a picture of is, a sewer clean out cap. This cap protects the entry to a pipe that would be used if needed to, clear a sewage stoppage to your home. This device is part of the homeowners own plumbing and needs to be maintained by the homeowner. My advice is, since you can’t screw it back on, do your best to secure the cap by the use of some sort of waterproof caulking. If this does not work, you can call a plumber to repair it.

Thank you for contacting the Bureau of Utilities with your question. Our records indicate that this issue has been resolved. Please contact us with any additional questions or concerns.