Tap Water for Indoor Plants: What You Need to Know

When you water your tap water, the untreated water that comes from your home faucet, often containing chlorine, fluoride, and dissolved minerals. Also known as municipal water, it’s convenient—but not always safe for sensitive indoor plants. Many people assume tap water is fine because it’s safe for humans, but plants don’t react the same way. What’s harmless to you can slowly damage roots, stunt growth, or cause leaf browning over time.

One major issue is chlorine, a chemical added to kill bacteria in public water systems. While it disappears after a few hours, many plants—especially tropical ones like peace lilies or spider plants—are sensitive to even small amounts. Then there’s hard water, water with high levels of calcium and magnesium salts, common in parts of the UK. Over time, these minerals build up in soil, forming a white crust on the pot’s surface and blocking nutrient uptake. You might see yellowing leaves or slow growth and blame your plant’s needs, when the real problem is what’s in your watering can.

Fluoride, another common additive, is especially tricky. It doesn’t evaporate like chlorine. Plants like dracaenas and lilies show tip burn—brown, crispy edges—because they can’t filter it out. And if you live in an area with soft water, you might think you’re safe, but that water can be too acidic or lack essential minerals plants need to thrive.

So what can you do? Leaving water out overnight helps chlorine evaporate, but won’t fix hard water or fluoride. Rainwater is ideal if you can collect it—clean, soft, and naturally balanced. Bottled water works in a pinch, but it’s expensive and not sustainable. A simple filter pitcher can remove chlorine and some minerals without breaking the bank. And if you’re serious about plant health, testing your water’s pH and hardness is easier than you think—you can buy cheap kits online or even ask your local water provider for a report.

Some plants, like snake plants or pothos, are tough enough to handle tap water just fine. Others, like carnivorous plants or ferns, need pure water to survive. The key isn’t to avoid tap water entirely—it’s to understand your plants’ limits and match your water to their needs. You don’t need fancy gear or perfect conditions. Just a little awareness goes a long way.

Below, you’ll find real guides from UK gardeners who’ve tested these issues firsthand. Whether you’re dealing with brown leaf tips, slow growth, or just wondering why your favorite plant isn’t thriving, the answers aren’t always in the soil—they’re in the water you’re pouring on it.