There are good reasons to try to unclog your drains before calling in the plumber. You might be able to save serious money. And it might even be a quick and easy fix. If not, you can always call the professional after trying it yourself. You can use these ideas to give it a good try without doing any harm.
The most common problems are with sink, tub, or shower drains, and with plugged toilets. There are steps to be taken in all these cases. The solutions offer here do not include chemical drain cleaners. There are good reasons not to use those, including safety and environmental concerns.
A few tools will be needed, if you want to give unclogging your drain a good try. Plungers come in several styles. The flat-bottomed one is most useful for sinks, while the extended-collar model works best for toilets. You might want ordinary household hand tools for undoing drain covers and such. And you'll want a pipe wrench if you plan to tackle removing a p-trap. If you are really serious about dealing with the issue, you probably want to have a snake or drain auger.
Before you start, make sure that you really have the problem localized. If all your drains are running slowly, you may have a problem in the drain system leading away from your home. Or, if you are on a septic tank system, you may have a problem there. Your tank may need to be pumped, or you may have issues with the drain field. Home plumbing systems are vented. It is possible that a problem occurs because the vent is blocked, and not because the drain is blocked. If you are not up to investigating that matter, best call on a professional.
Once you do get the local issue diagnosed, you can start with the easiest solution and hope for the best. Most sink stoppages are near the source, and most toilet blockages are within the accessible parts of the system.
You can check the strainer or other cover on the drain. Give it a good close inspection, possibly with the aid of a flashlight. Try to remove any solid material you find, such as hair in a tub or shower drain or vegetable material in a kitchen sink drain. That might solve your problem right there.
Next you can try the sink plunger. Take it easy. You don't want to splash the contents of that drain all around the kitchen or bathroom. If a gradual progression of plunging, from gentle to vigorous, doesn't work, consider the next step.
If the first part of the drain isn't where the issue is found, suspect the trap. Under a kitchen or bathroom sink you should be able to get at the p-trap. It's a U or P shaped section right below the sink. It's purpose is to block nasty and possibly toxic gases from returning into your home through the drain system. It may be possible for you to remove it yourself and clear a blockage in it.
Or you can try the snake. You can buy them in home supply stores quite reasonably. You feed the snake into the drain and turn the handle, or there are models that connect to an electric drill. If you are really familiar with your drains, or are willing to develop that familiarity, there may be access points beyond the sink. Look for them, then you can try the auger there. That about as far as most home owners are prepared to go.
An effort to open a blocked toilet usually starts with a plunger. The toilet plunger is the one with the extended collar on it. As with the sink drain, it is best to start the plunging action gently, and progress to more vigorous efforts if that doesn't work. Be careful about adding too much water. You don't want to start a flood of toilet drain contents.
If the plunging doesn't work, the snake comes next. Remember, there are different kinds of augers for sink drains and for toilets. The toilet auger will have some provision for protecting the porcelain from damage. Try the snake. If the blockage is in the toilet or near it, as is usual, that may clear the block.
If these steps don't cure the problem, there may be more serious issues further down the pipes, or even outside the house system. At that point, it is probably a good idea to get the situation looked at by a professional.