Possible causes:

Solutions:

1) Worn cartridge or cracked ceramic piece. 2) Aging or loose sealing ring. 3) Loose connection at the water inlet.

1) Replace the cartridge (preferably ceramic material). 2) Check and replace the sealing ring. 3) Tighten the connection between the angle valve and the faucet with a wrench.

Possible causes:

1) Dry water seal (common in U-type floor drains). 2) Hair and debris clogging the pipe. 3) Inappropriate floor drain type (e.g., T-type floor drain used in the kitchen by mistake). 

Solutions:

1) Regularly add water to maintain the water seal. 2) Use a drain cleaner or remove the filter to clean out debris. 3) Replace with a direct-flow sealed floor drain (preferably all-copper chrome-plated material).

Possible causes: 1) Poor material (zinc alloy prone to oxidization and breaking). 2) Excessive force during installation causing stripped threads. 3) Aging sealing gasket. Solutions: 1) Replace with a copper angle valve (a heavier weight indicates copper). 2) Tighten manually during installation, and then gently use a wrench to turn half a circle. 3) Replace with a silicone sealing gasket.

Possible causes:

1) Material prone to corrosion (e.g., iron or low-grade stainless steel). 2) Loose installation due to improper drilling or damp walls. 3) Long-term overloading with heavy items.

Solutions: 1) Choose 304 stainless steel or space aluminum material (lightweight and rust-proof). 2) Re-secure with anchors and apply waterproof glue. 3) Avoid hanging objects over 5kg, and regularly wipe off water stains with a dry cloth