There will be less maintenance if your pond is not under trees. Most aquatic plants will grow better in full sun. These can be placed on the patio and provide many of the same benefits as a built-in pond. There are numerous tub kits available that can be as simple as adding water, a pump, and some plants. They can also be moved inside in the winter as long as good lighting is provided for plants.
Pond liners Pond liners keep water from seeping into the soil.
Even in heavy clay soils, a liner is necessary. You can buy rigid pond liners in a variety of shapes. These are durable and may include built-in waterfalls. Many are quite small. Use a liner specifically designed for pools.