You can spend as little as $100.00 for a small water garden with plants while spending anywhere from $1,000.00 to $10,000.00 for full size water gardens with filters, lights, waterfalls, plants, statuary and fish. A pond addition to the home is an investment that pays for itself. It not only provides enjoyment year round but can also possibly add property value. If desired, the home owner can also have a professional contractor install the water garden. You should discuss all budget and options with your contractor.