How to Test Your Water Quality for Coffee Brewing
Testing your water takes 5 minutes and a $15 TDS meter. Two tests — TDS and hardness — tell you everything you need to know about your water for coffee purposes.
⚡ Quick Answer
Buy a TDS meter ($10–20) and test your cold tap water. If TDS reads 75–250 ppm, your water is likely fine. If it's below 50 ppm, add minerals. If above 300 ppm, filter or use bottled water. For hardness specifically, use an aquarium hardness test strip ($8–12 for a pack) — target 75–150 mg/L as CaCO3 for espresso.
🎯 Minimum testing setup: $15 TDS meter + water from your tap. Takes 60 seconds. Tells you your baseline and whether you need to do anything at all.
⚙️ What to Test and How
Test 1: TDS (Total Dissolved Solids)
Tool needed: TDS meter ($10–20 on Amazon). Most popular: HM Digital TDS-3 or similar.
How: Dip meter tip in cold tap water for 5–10 seconds. Read the ppm display.
Interpret: <50 ppm = too low, add minerals. 75–250 = good range. >300 = too high, filter or blend.
Test 2: Water Hardness
Tool needed: Aquarium water hardness test strips ($8–12) or GH/KH test kit. Or use your local water authority's annual report (free online).
How: Dip strip in cold water, compare color to chart within 30 seconds.
Interpret: Very soft (<50 mg/L) = under-extracts, damages machine. Moderate (75–150 mg/L) = ideal. Hard (>200 mg/L) = heavy scale buildup, consider filtering.
Test 3: Chlorine (Optional but useful)
Tool needed: Swimming pool test strips (usually included in multi-packs).
Interpret: Any detectable chlorine affects coffee taste — a Brita filter eliminates chlorine in one pass. Heavily chlorinated tap water often smells like a swimming pool; activated carbon filter fixes this completely.