Typical signs
- Verdigris on copper, white deposit on brass or rust on galvanized steel.
- Periodic dripping, swollen braided connector or dried trail below a nut.
Where it is often found
- Under sinks, behind toilets, near water heaters, valves, faucets and appliances.
What it can mean
- Worn seal, over- or under-tightening, vibration or galvanic corrosion.
- Slow pressure leak or poorly managed condensate.
What to check next
- Wipe dry, observe and recheck after use.
- Check support, hose strain and metal compatibility.
Reasonable immediate actions
- Close the local stop if leakage worsens; prepare absorbent materials and a pan.
When to stop and call a professional
- Extensive corrosion, seized valve, brittle pipe, hidden-cavity leak or water heater/gas involvement.
Prevention
- Proper support, periodic inspection, replacement of ageing flex connectors and control of dissimilar metals.