The water quality used to raise eels must meet the fishery water quality standards stipulated by the Chinese government and the special requirements of water for raising eels, so as to ensure the edible quality of commercial eels, the produced eels have no peculiar smell, and the accumulated concentration of harmful substances in the body does not exceed the hygienic standards.

As long as the above water quality standards are met, rivers, lakes, reservoirs, springs and groundwater can be used to raise eels.

According to the actual situation for many years, spring water and reservoir water are good, and the quality of source water is clear.

The number of plankton and bacteria in ponds and lakes is generally high, and the water in rivers and ditches is greatly affected by seasons, with large flow in rainy season and good water quality.

In dry season, the flow rate is small, and the content of organic matter and suspended matter is often too high.

Some characteristics of source water can be improved, for example, the manganese content and dissolved oxygen content of groundwater are too low, winding rivers can be built to extend the time and distance of water flow, natural sunlight can be used to raise the water temperature, and water flow or aeration can be used to increase the dissolved oxygen content in water.

When the pH value of water is too low, it can be slightly adjusted with lime. If the content of plankton, bacteria and suspended solids is too high, it can be treated with disinfectants and precipitants and filtered.