What are the main issues with rainwater harvesting?

• With the increased emphasis and promotion by domestic authorities on rainwater utilization, the domestic market for rainwater collection is showing a positive trend. However, there are still some issues hindering the progress of rainwater resource utilization. Further understanding of the nature of urban rainwater resources and their role in addressing urban water problems is needed.
• What are the remaining issues? Firstly, in some cities, the municipal construction and planning departments have not yet recognized or fully understood the value of urban rainwater collection, still treating it as a disaster and doing everything they can to drain it away. Secondly, the public's understanding of rainwater collection is insufficient; when promoting the comprehensive utilization of rainwater systems in some areas, many people often ask, "We're not short of water, why do we need to do this?"
• Many individuals and businesses are unaware of the existence of rainwater collection systems. Additionally, there is a lack of understanding regarding the methods and effects of urban rainwater recycling. Common misconceptions include: the limited role of rainwater resource utilization, primarily focusing on direct use of rainwater and water conservation, while overlooking its functions in mitigating urban flood risks, controlling runoff pollution, and improving the city's ecological environment; and the belief that rainwater discharged can replenish groundwater, etc.
• Therefore, the rainwater collection project often encounters some challenges: Firstly, we invest a great deal of resources and effort to drain away the rainwater, which not only wastes a large amount of freshwater resources but may also lead to water environmental pollution; secondly, we have to deal with the severe water shortage issue.