There are two key components of conserving a water source for long term use. The first part is using water efficiently and making sure that you get the most use out of each drop. The second part is protecting that water source from any potential sources of contamination.
Most of the sources we can control, such as moderating the use of fertilizers and pesticides or keeping live stock away from above ground water sources. However, the natural filtration system of the aquifer provides enough protection that the before mentioned strategies have some leeway and are not the biggest threats when it comes to aquifer contamination.
The biggest threat comes from irresponsible users contaminating the existing system. Most fertilizers and pesticides require water to be applied to lawns or orchards. Direct contact of a water source (such as a hose) and a chemical presents an opportunity for contamination.
Spray tanks are a major concern for contamination. If a hose is directly attached to the tank and there is a drop in pressure, then it is likely some of the chemicals in the tank will be back siphoned into the system.
It is provincial regulation that there must be a 15 cm air gap between the filler hose and the fertilizers or pesticides. Fertigation (direct injection of fertilizers via the water system) also presents an area of concern. Fertigators are required to install back flow prevention devices that must be inspected by a certified professional. These regulations must be adhered to, contamination of the water system can result in widespread contamination and sickness if these chemicals are ingested by other members of the community.