Leach vs. Leech: Drain Chemicals or Bloodsucker?

The Distinction

• Leach = to drain away by filtering; to remove substances through liquid
• Leech = a blood-sucking worm; someone who exploits others

Using Leach

“Leach” describes a chemical or filtering process:

• “Chemicals leach into the groundwater.” ✓
• “Rain can leach nutrients from the soil.” ✓
• “The toxins leached out over time.” ✓
• “Coffee is made by leaching flavor from the beans.” ✓

This is a technical term often used in environmental and scientific contexts.

Using Leech

“Leech” refers to the creature or exploitative behavior:

The creature:

• “Doctors once used leeches for bloodletting.” ✓
• “A leech attached to his leg in the swamp.” ✓

The metaphor:

• “He’s a leech who lives off his friends.” ✓
• “Stop leeching off your parents.” ✓
• “The company leeches resources from the community.” ✓

Memory Trick

• Leach = chemicals and liquids (think “bleach” which also involves chemicals)
• Leech = the double E looks like two eyes of the creature watching for prey

Quick Test

Talking about substances draining through soil or water? → leach Talking about parasites or exploitation? → leech