A garden pond that uses grey water is a pond that's replenished with used water from household activities. Toilet water is not used in a grey water pond, but water that's been used to wash dishes and take showers, for instance, is all called grey water.
Grey Water Garden Pond
The difference between a garden pond maintained with grey water and once that you use new water with is the way you run the water to the pond, and the power of your filtering system. A system of piping the used water (except from the toilet) from the house to the pond will be necessary. To avoid a murky look in the pond, the filter will probably need to be cleaned more often.
Plants in a garden pond supplied with grey water can actually flourish because of the extra nutrients in the water, much like the way kitchen scraps turned into compost is the perfect fertilizer for plants growing in the ground. Reeds are an ideal plant for a garden pond that uses grey water. Fish also do well in a grey water environment, so you can use "recycled water" and less fresh water while maintaining a beautiful garden pond.