From its imaginative and unusual name, you are forgiven if you think of a sewer snake is a type of reptile. A sewer snake, or commonly referred to as drain snake, plumbing snake, or drain auger, is a tool used to unclog drain lines. One of its most noticeable characteristics is the long flexible metal wire, with a corkscrew auger attached to the end of the line. It can be powered either by hand or by electricity. It rotates downward into the drain line to reach the clog. When it does reach any obstruction, the auger will shred any physical object so everything can be flushed away normally. In some cases larger objects are physically pushed down and out of the drain line. 
A sewer snake come in a variety of sizes, and for various applications. Some models are designed with specific configurations to handle a specific job, such as for a toilet clog. Several types are available both for home usage and for commercial-grade applications. Many hardware stores even provide drain augers for rent, allowing homeowners to unclog drains without calling professionals. However, some clogging problems are too difficult to handle, in which case a heavy-duty sewer snake is required. Professional plumbers almost always carry some drain augers in their vans as one of their standard plumbing tools.
Commercial and Home-grade Drain Augers
The basic design of a mechanical drain snake consists of three major parts:
1. The metal wire, also called a cable or snake.
2. The auger, or blade at the end of the cable.
3. And a crank or motor to operate everything.
When the crank is turned clockwise, the auger attached to the metal wire will go out from the housing. When the crank is turned counterclockwise, the auger goes backward into the housing. The auger does the jobs in two ways; as it moves, it can catch large debris then carry it out of the drain or it can simply break up the clog so you can flush it with water more easily.
Hand Auger & Small Electric Auger
The biggest differences between a home-use and commercial-grade sewer snake are the dimensions and the power. While the basic design remains the same, or at least they use the same operating mechanism, size of components and motors vary greatly. A commercial-grade drain auger used by professionals usually is powered by a powerful motor, which can be attached with different sizes of cable and augers. The largest wires (snakes) and augers are used for unclogging main drains, and larger diameter pipes. The diameter of the main drain is significantly larger than those under the sink. When clogging occurs, the culprit is typically larger as well, meaning they require larger tools to get unclogged. A high powered motor allows the auger to travel more easily through stubborn clogs, and they can reach much farther compared to their home-use counterparts. The larger the diameter of the snake and the horsepower of the motor, the further it can be successfully inserted into a pipe.
The more advanced commercial-grade drain snake can even have a video camera connected to an external screen above ground. Professional plumbers will be able to see everything inside the drain in high definition, and check for possible damages such as holes or cracks. Sometimes, clogging happens not just because of accumulated mud or debris, but due to damaged pipes. The camera makes it easy to inspect the damage and pinpoint the exact location that needs repairing.
A home-grade drain snake is typically only effective for small drains, and it has a limited reach as well. Many homeowners only use or purchase simple drain snakes, mostly because they are affordable and easy to use. The effectiveness is not really a consideration when making the purchase. Some professionals recommend cleaning the home drains once every other year, so spending hundreds of dollars for a heavy-duty auger makes little sense. A drain snake with a 50 feet long cable, and half an inch in diameter, is good enough to get rid of common clogs such as food, hair, or diapers, and such a model is less expensive than a commercial grade one. Also, most homeowners typically choose to use chemical drain cleaners, rather than operating an auger.
The most affordable model of all sewer snakes is hand-powered, although the price for the smallest electric ones is not that far off. Some models are designed to attach to a handheld power drill so a homeowner can rotate it more easily down a small drain. Although the drain auger has similar characteristics with a power drill, they have far form the same effectiveness.
Operating a small sewer snake is not difficult; all you have to do is turn the crank or press a button to make it go down or up the drain. It is best to pull it back up as you feel resistance to take out the clog. Forcing it to go down may only send the clog further into the pipe, or tangle the snake itself inside your plumbing. A sewer snake stuck inside your plumbing only exasperates the situation.
Sewer snake tangled inside a broken pipe
A Sewer Snake (Drain Auger) Has Various Types
There are at least three different types of drain augers available, and each is designed to handle specific jobs. Before you rush into your local hardware store to buy or rent a sewer snake, you may need to consider the types of drain systems you have and how bad the problems are. Purchasing the wrong tool for the job can be a complete waste of money.
Toilet Auger/Closet Auger
This type of drain cleaning tool has a relatively short auger attached to a hook-shaped metal cable/tubing. The shape makes it easier for the cable to pass down the toilet bowl, to the point of the clog. The auger is usually covered by a plastic to prevent scratching the porcelain of the bowl. In most cases, toilet clogs occur in the trap attached to the bowl, so short cable should be sufficient. In some cases the toilet has to be physically removed the clear the blockage
Hand Spinner/Hand Auger
Some models of this category are designed to work with a handheld power drill to rotate the spinning drum canister. Others can be operated by rotating the lever attached to the canister. A hand spinner has a different specification from toilet auger, so you should not use them interchangeably. The cable and auger of a hand spinner can damage or get twisted inside a toilet.
Drum Auger/Sewer Snake
Compared to the previous two models, this is the most powerful and versatile. It is motorized and equipped with modular blades. A drum auger is strong enough to cut down roots inside a sewer pipe. This style of sewer cleaning machine come sin various sizes, the largest of which needs two men to safely move into place and operate. The larger style sewer cleaning machines cost thousands of dollars, and should only be operated by a professional. The right tool in the wrong hands is never a good recipe.