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If you're collecting a sample from the tap, let the water run for at least 1 minute. Then, fill the glass so it's at least of the way full. This is more than enough to spot anything out of the ordinary in a sample. For pools of water, scoop up a sample with the glass. You don't need to sterilize the glass first. Think of the crystal clear water at a beautiful beach. Clean water looks transparent and doesn't have anything floating in it. If you can't see your hand on the other side of the glass, you're probably not going to enjoy drinking that water. Anything floating in the glass could be a sign of bacteria or other problems. Before getting on the phone with your water department, set the glass down and wait for a minute. Sometimes milky water clears up right away. That means the color came from air bubbles, so your water is safe to drink. Hard water is water that has calcium, magnesium, and other minerals in it. The minerals cause the water to look a little cloudy. It is usually safe to drink but can be fixed with a water softener to avoid damage to your plumbing. Treat water with colored particles. For example, brown or orange particles are from rusty pipes while black ones come from rubber. Call a plumber to fix the problem. Even if your water doesn't have anything floating in it, it may still not look completely clear. Discolored water not only looks gross but is a big red flag. These colors also turn up as stains on your dishes, clothing, bathtub, and other places. Use the strange coloring to figure out the source of the contamination before paying for a more comprehensive purity test. For instance, brown water is a very common problem. The contamination comes from dirt and other sediments, which you might see settle at the bottom of the glass. Red and orange colors come from rusty pipes. Black could mean you have lead in the water, a very toxic metal that also often comes from pipes. Green usually means algae grew in your water supply, so don't drink it. If it has a blue-green coloring, it could be copper instead. A black stain could also mean mold. If the water smells bad, play it safe by assuming that it is going to be unsafe to drink. Sometimes water has that distinct rotten egg smell of sulfur, which comes from bacteria in the water. Other times, it could have the smell of a swimming pool because of chlorine contamination. If your water smells like nail polish or varnish, that could mean that some chemical leaked into the water supply. It might be from a home improvement project, for instance. Purify water by filtering and boiling it to remove contaminants. If you're using municipal water, call your city or utility company. Contact your local government for more information. If you don't see anything unusual about the water, taste a little bit of it with the tip of your tongue. You can usually detect polluted water right away. Bitterness often means metal in the water, so order a more complete water test as you look for problems. If you detect salt instead and live near the sea, seawater could be leaking into your plumbing. Clean water has a flat, bland taste. If your sample tastes metallic or like a fizzy soda, don't risk drinking it. Keep in mind that you can't always taste water quality issues. Things like bacteria and pesticides may not be easy to detect. Normally you can tell by looking at the water, but double-check with a lab test if necessary.
Fill a clean, clear glass full of water. Hold the glass up to the light to see if it looks cloudy. Look for color changes in the water. Smell the water to see if it smells harsh or rotten. Taste the water for bitterness if it looks safe to drink.