First,
you need to determine if it is local waste produced in your home that
can't get out due to a blockage in the main line leaving your home, or
if it is waste from the sewer system coming back in (called a backflow).
A blockage can occur if a portion of the
line has broken, but generally a blockage is caused by roots that have
grown into the line, or by something flushed down a toilet that has
lodged in the drain pipe.
When this happens, you will see evidence of your basement drain backing up as the lowest point in the system (generally the basement drain overflows) is where the evidence is visible.
Chemical products may work to open the
drain, but running a snake through the line is generally necessary. In
the case of roots of invading the basement drain line, a power snake
with sharp cutting blades must be used to cut through the roots.
With your own local waste backing up
it's one thing, but when nasty, contaminated waste from hundreds of
neighbors starts pouring into your home, it becomes a whole different
issue.
In this case, usually due to high levels
of rainfall temporarily raising the water overall table, the system
will be overwhelmed. If the lowest drain in your basement (or other
shower drain or toilet) is lower than this temporarily raised water
level, you will find your basement drain backing up. In some
cases the pressure created by the raised water level is so great that
water raw sewage will be spewing several feet into the room from
basement drains.
There is only one way to prevent this particular condition of your basement drain backing up;
the installation of a gate to keep the unwanted reverse flow out. Some
of these gates are manual and must be manually inserted or manually
turned closed.
The best are automated solutions called "Backwater Valves" or "Backflow Preventers"
A Backwater Valve
automatically senses a reverse flow (water flowing the wrong direction
and back into your home) in your main line and completely closes it off
from the sewer system outside. This prevents your basement drain backing up.
A Mainline brand 4963 Backwater Valve installed in the main line below your basement floor is one of the most economical and effective ways that you can prevent your basement drain from backing up.
If I've heard it once, I've heard it a thousand times, "I just had my basement drain overflow, and naturally I was I was . . . at work . . . asleep . . . out of town . . . on vacation. In these cases, the fact that a backwater valve
works automatically is worth the associated costs of the valve and
installation. As many know, what's as stake is thousands of dollars of
damage to the basement living space, not to mention the health hazards
caused by the bacteria in the raw sewage produced by hundreds or even
thousands of your neighbors.
Some people simply insert a plug into
their basement drain in an attempt to stop a basement drain backup, but
in a case where groundwater comes in when there is not a mainline
backup, the end result is also flooding. Additionally, the force of
incoming water can simply push these plugs up and out of the way leaving
you unprotected. A good automated backflow valve is the best solution
to avoiding a basement drain overflow that lets water in the basement.
The single biggest advantage of the
Mainline brand Backwater valve is that it uses a patented normally open
design. When properly installed with a required minimum slope of 2% (or
more), water and effluent leaving the dwelling works to continuously
self-clean the gate, keeping it free and ready to seal when you need it
most. There are hundreds of cheap normally closed valves on the market
that are destined to fail as debris accumulates at the sealing point.
The patented Mainline brand is the single brand backwater valve available with a self-cleaning normally open design.
source: backwater-valves.com
Just imagine for a minute, you walk down to your 
A sump pump is like a vigilant, hardworking little robot standing sentry in your