First things first: buy a TDS meter. They’re cheap—like, $10 to $20 cheap. You can get them from any online store or a hardware shop. No subscription needed. No monthly fee. It’s a one-time purchase for the water detective in you.
Pop it open, and you’ll see two little metal prongs. Those are the probes. They’re the brains of the operation. Or, more accurately, the nose. They sniff out dissolved solids by measuring how well electricity flows through the water.
Why electricity? Because dissolved salts and minerals conduct electricity. Clean water? Not so much. So the meter reads the resistance and spits out a number. Science magic!
Step 1: Rinse the Probes
Don’t just jam the meter into your glass. That’s rude to the water. Rinse the probes with a bit of distilled water first. Or just tap water if you’re impatient. Just don’t use your own spit. Trust me on this one.
Wipe them dry with a clean cloth. You want no leftover residue from last week’s weird experiment. A clean start gives you a clean reading. Your water deserves that much respect.
Step 2: Fill a Glass with Your Water
Take a normal glass—nothing fancy. Fill it up with the water you want to test. Let it sit for a minute so any bubbles settle. Bubbles mess with the reading. They’re like little liars floating around.
If you’re testing tap water, run it for a few seconds first. You don’t want water that’s been sitting in the pipes all night. That’s the water’s version of morning breath. Ew.
Total Dissolved Solids | TDS of Different Water Samples | Experiment
Step 3: Dip and Stir (Gently!)
Turn on your TDS meter. Most have a simple on/off button. If yours doesn’t, it probably turns on automatically when you dip it. Technology is wild.
Submerge the probes about an inch into the water. Don’t go deeper than the “max” line—usually marked on the meter. Then stir it around gently. Not like you’re mixing a cocktail. Just a soft swirl.
Wait for the number to stabilize. It’ll jump around for a few seconds. That’s normal. It’s just the meter being dramatic. Let it settle.
Step 4: Read the Number
Boom. You’ve got your reading. It’s in parts per million, or ppm. Here’s a cheat sheet so you don’t panic:
0–50 ppm: Basically pure. Like rainwater or distilled stuff. Boring, but clean.
50–150 ppm: Sweet spot. Your typical tap water. Good for drinking, great for tea.
150–300 ppm: A bit hard. You might notice a taste. Your kettle might get grumpy.
300–500 ppm: Hard water. You’ll see spots on glasses. Your hair won’t thank you.
Total Dissolved Solids: Understanding Water Quality Indicators – Water
500+ ppm: Yikes. That water’s been through a lot. Might need a filter.
Rhetorical question time: Do you really want to drink that if it’s over 500? No, you do not.
