“Water, water everywhere, Nor any drop to drink” (Coleridge, 1798) are lines from “The Rime of the Ancient Mariner” referring to sea water. Do those same lines of poetry apply to lake water? It depends; it definitely applies to consumption of untreated lake water. However, with the proper set up, use and maintenance of a home treatment system, it is possible to use lake water for domestic purposes.
The municipal water sources for many communities are lakes. Treatment systems designed and employed by municipalities that use lake sourced water are typically complex and require constant monitoring and maintenance. Private residential treatment systems might have some components that are similar to municipal systems and are typically designed based on a number of factors including:
Location of intake, average daily water use, contaminants and type of use (consumption, cooking, irrigation).
Our lake contains biological as well as chemical contaminants (the chemical contaminants are both man-made and nature-made). An effective system can remove or reduce contaminants to an acceptable level if water is to be used inside the home for consumption, cooking or cleaning. The system might be comprised of several elements to remove suspended particulates, man-made chemicals (oil, gasoline, etc.), biological’s (E. coli, cryptosporidium, zebra mussel larvae, etc.) and unwanted tastes and odors.
Particulate removal should begin at the point of intake as the first line of defense. This would be some type of filtration medium that removes any particulates 20 microns or greater in size. This includes zebra mussel larvae. Without this first line of defense, zebra mussel larvae could enter the home’s entire water system and grow in every water line inside the home. If this occurs, mussels will continue to grow until they entirely block the flow of water and would require all of pipes removed and replaced at costs that might exceed $10,000. An inexpensive filter at the point of intake would be the easiest course of action to address that risk. Additional sediment or particulate filters (1 to 5 microns) can be installed inside the home, which improves water quality and makes it easier to access the filters for replacement or cleaning.
Chemicals and unwanted tastes and odors can be removed with a whole-house carbon filtration unit. Additional point-of-use carbon filters at a kitchen sink for example, will further improve the taste and reduce the “lake” odors from drinking water.
Biological’s (other than zebra mussel larvae) are not necessarily removed from the water, but are instead rendered harmless by disinfection elements in the treatment system. Chlorination is an effective and economical means for disinfection and is typically paired with carbon filtration to reduce the chlorine taste and odor. Ultraviolet water treatment units are also an economical way to disinfect water.
The design, sequencing, layout and sizing is best left to professionals that specialize in making lake water suitable for domestic use.
A final and most cautionary note: there are no certified treatment systems or elements for the removal of toxins created by blue-green algae in private residential treatment systems. Boiling or disinfecting water will actually cause blue-green algae cells to burst and release toxins into the water. Municipal water systems that are susceptible to blue-green algae have industrial means for monitoring and removing the toxins. They typically have trained technical staff for analyzing water and taking immediate remedial action. Unfortunately there is no “scaled-down” version of these complex systems for private residential water treatment systems. Other than visual observation of blue-green algae collecting on the surface of the water, there are no means for immediately testing for or determining the presence of blue-green algae and the toxins they might create. Most home water treatment system professionals are unaware of the dangers of blue-green algae toxins and that there is no method of treatment.
While most contaminants can be eliminated, the risk of coming in contact with blue-green algae toxins remains until science or invention discovers an effective treatment. The risk/benefit decision is of course up to the individual homeowner.