Rain Barrel Practicality
Rain barrels can help reduce the use of relatively expensive, treated water for nonpotable applications such as watering garden and landscape plants. Alternative sources of nonpotable water are increasingly important in chronically or seasonally arid parts of the country. Rain barrels (Figure 1) are relatively inexpensive to obtain and install, and residential costs are typically recovered within 3–6 years of installation (Logan 2014).
Rooftop collected rainwater has been tested on container plants as well as those planted into gardens and landscapes. In all cases good results have been seen, with no plant disease or disorder problems apparent (Chen et al. 2003; Islam et al. 2013). But rain barrel water is untreated and unregulated. There are legitimate safety concerns about exposure of people, pets, and the environment to rain barrel water.
Many studies have identified rain barrels as reservoirs for toxic materials and pathogenic microbes (Hart and White 2006; Lye 2009; Schuster et al. 2013). Possible rain barrel contaminants fall into two general categories: biological and chemical.
- Metals, especially heavy metals
- Particulates (adsorb other chemical contaminants)
- Pesticide residues
Researchers have looked at nutrient loads, heavy metal content, pesticide residues, and microbial contaminants in rainwater collection systems in hundreds of studies from all over the world (Table 1). In North America, the main concerns are fecal contaminants and heavy metals.