A puddle under your machine doesn't always mean something expensive is broken. Work through these in order — they're listed from most common and cheapest to fix, to least common.
01Worn portafilter gasket
The rubber gasket that seals the portafilter against the group head hardens and flattens with use. Once it loses its seal, water sprays out sideways during extraction instead of leaking steadily.
02Loose or worn drip tray / water tank seal
If the leak appears under the machine rather than during extraction, remove the water tank and check the silicone valve at its base. These valves can warp or collect mineral buildup over time and stop sealing properly.
03Overfilled portafilter
Too much ground coffee (over-dosing) prevents the portafilter from seating fully against the gasket, which lets water escape at the edges. Check your dose against your basket's rated capacity — most single baskets hold roughly 7–10g, doubles 14–20g, but this varies by machine.
04Scale buildup inside the boiler or valves
Mineral scale doesn't just slow your machine down — it can prevent internal valves from closing fully, causing a persistent drip even when the machine is idle. This is one of the most common outcomes of skipping descaling for too long.
05Cracked or brittle internal tubing
Rubber or silicone hoses inside the machine become brittle with age and heat cycling. This usually shows up as a leak from underneath the machine's housing rather than from the group head or tank, and typically means opening the case to inspect — worth doing only if you're comfortable with basic disassembly, or better left to a repair technician.
06Faulty solenoid valve
The solenoid valve controls water flow into the boiler. When it fails to seat properly, water can leak past it continuously. This is a part replacement rather than a cleaning fix.
07Cracked water reservoir
Less common, but check the tank itself for hairline cracks, especially near the base or handle, particularly on plastic tanks that have been dropped or over-tightened into place.
| Where it leaks | Most likely cause |
|---|---|
| During extraction, from the portafilter | Worn gasket or overfilled basket |
| Underneath, machine idle | Scale in a valve, or cracked tubing |
| Near the water tank | Tank valve or cracked reservoir |
Start with the gasket and dose — together they cause the large majority of home-machine leaks, and both are free or near-free to rule out before you consider a part replacement.