Urbanization and construction increases the chances for non-point source pollution (NSP) in that by replacing soil and plant life with concrete, storm water cannot absorb into the ground and washes off into the inlets. Often this runoff is polluted with chemicals and particulates as the water flows over different surfaces and collects materials and chemicals during its journey.

Construction companies have long worked to keep these materials from increasing due to water runoff from an active construction site. As such, they have several measures which they take to protect the environment from chemicals and particulates. Most of the time, these measures are taken directly at the storm inlet drains on or near the site. These drains are protected by various types of filters, known as inlet filters.

Depending on the grade of the land, the amount of runoff expected and the type of particulates predicted, construction mangers use the most effective inlet protection method. These may include excavation around the inlet drain, creating an area to collect the sediment, using stone and block inlet protection, curb drop inlet protection or fabric drop inlet protection.

Another consideration when selecting the right option for inlet protection is the amount of time needed to construct/install the filter as well as the expected maintenance time for the filter. Many construction companies prefer using filters such as the fabric drop inlet filter because of its versatility, time and cost effectiveness.

When looking for a fabric drop inlet protection system, one should ensure that the fabric is of the highest quality and industrial strength for durability. Fabric drop inlet filters are available for nearly any size or shape of inlet drain. These filters resemble a large sack which hangs below the inlet drain, poised to catch debris and trap it before it enters the wastewater. Some of these filtration units has additional or optional absorbents available to collect chemicals from the water as water passes through the filter.

With a minimum time requirement to install, maintain and remove, fabric drop inlet filters are extremely time efficient to use. One of the added benefits of a fabric drop filter is that these filters are reusable several times over, making the initial cost go further. The required absorbents need to be replaced according to the manufacturer's recommended schedule. However, be sure to keep in mind that the cost for making certain inlet filtration systems may be slightly more expensive than for filtration without the optional chemical absorbents added.