When a drain is blocked, it can be rather instinctive to just reach for some chemical drain cleaner. Of course, there's an easiness to this solution. You just slosh the caustic chemicals down the plughole and wait for the drain to clear. Having said that, the words caustic and corrosion might make you uneasy, but these are apt words when talking about chemical drain cleaners. The toxicity of these types of cleaners, in addition to the noxious fumes they can release, might make you think twice before pouring it into your drains. However effective they might be, surely there's a less toxic, more environmentally friendly way to clear your blocked drains?
Chemicals can be avoided when the blockage only appears to be light, since they're not necessary at this stage. Simply fill your electric kettle and turn it on. Once the water has boiled, pour it into the blocked drain in a slow, steady stream, being careful to avoid splashbacks. Add water to the sink and let it drain to see if the blockage has been removed. If the water is still slow to drain, you can add another step. Once the water has drained, sprinkle a teaspoon of baking soda into the plughole. Wait a few minutes (now is a good time to switch the kettle on again) before adding boiling water once again. The baking soda when combined with the water will create an oxidation effect, with small bubbles helping to dislodge the blockage.
A moderate blockage is generally where you would automatically use a chemical drain cleaner, but it's not needed. You will need to make a trip to your local hardware shop to pick up an environmentally friendly bacteria-based drain cleaner. Follow the instructions on the packaging, but you'll basically be releasing billions of bacteria into the drain that will slowly eat their way through any blockage. A periodic dosage of bacteria-based drain cleaner can also prevent your drains from becoming re-blocked. Though slower-acting than a chemical drain cleaner, you can completely avoid the necessity for toxic chemicals.
Surely a heavy blockage is when you would want to call in the chemical calvary? A heavy blockage can prevent usage of the drain altogether, but caustic chemicals can do more harm than good. Excessive usage (which might feel necessary with a heavy blockage) has the potential to corrode your pipes, and a broken pipe is far more problematic than one that is merely blocked! This is the time to call in the blocked drain specialists, namely your plumber. A heavy blockage might be more serious than you originally thought, and the plumber can safely remove it in its entirety, without the need to release toxic chemicals into the drain.
A blocked drain can be a massive inconvenience, so it's good to know that there are convenient ways to fix the problem without resorting to harsh, potentially dangerous chemicals.