One of the most common wastewater questions during the summer months, and definitely during times of drought is about the water level in lagoons. Many say the water level stays at only about 2 feet or even less and ask if that’s a problem, and if so, how do they keep the water level higher?

For residential lagoons to function at their full potential the water level should be a minimum of 2 feet and a maximum of 5 feet in depth. So, a lagoon with a water level at 2 feet is just on the edge of maintaining full functionality to provide treatment processes for household wastewater.

Periods of drought often negatively impact the water levels in a lagoon. When this happens, additional water often needs to be added to the lagoon to raise the water level and allow for proper functioning to treat the wastewater within it. This typically means running a hose out to the lagoon to bring the level up.

Low water levels in a lagoon are most commonly the result of the lagoon being “oversized” for current use within the home. Lagoons, like all wastewater systems in Nebraska, are required to be a certain size based on the number of bedrooms in a home. When the lagoon is built, the home may be fully occupied by a family and so there are more people using more water. As children grow and move away or if a home is sold to different people with different water use patterns, the lagoon may be somewhat larger than is necessary. 

Less commonly, low water levels can also be a result of a malfunction in the design of the lagoon or problems with maintenance of the lagoon such as allowing too much vegetation to grow around the lagoon.  The vegetation can draw moisture out of the berms of the lagoon and make some, although not a large, impact on the water levels.  Certain vegetation such as duckweed or cattails can also grow on the surface or within the lagoon itself, drawing water up into the plants and impacting the actual treatment processes of the wastewater within the lagoon.

Vegetation can be managed by a homeowner through careful chemical or mechanical removal of nuisance plants such as duckweed or cattails from the lagoon itself. It is imperative that you follow all directions and take safety precautions. Vegetation on the sides, or berms, of the lagoon is part of the proper function and maintenance of a lagoon. Mowing the vegetation to a height of approximately 6 inches can be done by the homeowner and should be done regularly.

If you suspect your low water levels may be from a structural issue within the lagoon or wastewater system, you should consult with a Nebraska certified wastewater professional.  Additionally, a certified professional may be able to examine your home system to make recommendations on use patterns for the specific system.  Otherwise, low water levels because of a change of water use within the home can be difficult problem to solve. If the water level in a lagoon stays 2 feet in depth it should be functioning to treat wastewater. The biggest concern comes in the winter where you will need to spread out warm water use to ensure that the lagoon does not freeze solid during extreme cold periods. 

For more information on residential wastewater and drinking water visit: water.unl.edu. To find a Certified Onsite Wastewater Treatment Professional in your area go to: https://deq-iis.ne.gov/zs/owt/businesses/

*This article is adapted from prior content by Meghan Sittler, former UNL Extension Educator.