Pondless waterfall maintenance is easy due to the fact that the pondless waterfall is practically maintenance free. Pondless waterfalls do not require a lot of the maintenance as opposed to what would be required to maintain a waterfall with a pond, especially one with fish. Minimal maintenance may be needed from time to time if something goes wrong or needs cleaning.
Because the water is constantly moving and is not lying stagnant, there should be no chance for algae to grow. If algae growth does occur and accumulate over time enough to be noticeable, then the water can be treated monthly with an algae control product for ponds or until the problem clears up.
Live fish should not be placed in a pondless waterfall as there is no place for them to swim and they would swim into the pump that circulates the water back to the top of the fall. Fish would therefore not survive long in a pondless waterfall. This actually makes the pondless waterfall more maintenance-free than one with a pond with fish that must be fed and which would necessitate having the water treated to deal with fish waste products. However, birds and other small wildlife will be attracted to the waterfall, making it enriching and educational as well as more enjoyable.
Some aquatic plants or other green plants can be added to the edges of the waterfall and around and even in the stream bed to enhance its beauty. If these are present, they will have to be cared for regularly as if they were in a pond. That means dead leaves and stems should be removed periodically. Unwanted growth such as weeds may also have to be removed.
If the automatic fill valve is working correctly, there should be no need to add water to the waterfall system. If the fill valve is not working, it should be repaired or replaced. A leak in or around the edge of the liner could cause water loss. So could splashing of water out of the waterfall. Evaporation from long periods of dry weather or in a dry climate could cause more evaporation of the water from the system. If for some reason there is a noticeable amount of water loss, water can be added with a garden hose.
If the water becomes muddy, the water could be drained and the system flushed out with clean water. A filter might be desirable if this happens; however, normally this would not be necessary to keep the water clean since it is constantly being recirculated. Also make sure the equipment is working properly.
The pump does not have to run 24 hours a day. Electricity can be saved as well as wear and tear on the pump by turning the waterfall off part of the day with a timer or a remote control switch. The waterfall can also be turned off during long periods of absence, such as when travelling. The pump can also be turned off during the fall and winter when it is too cold to sit outside and enjoy.
Leaves and other debris. This will probably only need to be cleaned out once a year. This can be done when the waterfall is turned off for the winter. When the waterfall is drained and dry, the leaves can be blown away with a leaf blower. If a lot of leaves fall in the waterfall, they can be raked out carefully when the yard is raked.
This should not be a problem as long as everything is working properly.
You need only do what is necessary to keep the pump, piping, and other equipment of the waterfall in good repair and unclogged. If any of these is seriously damaged, clogged, not working or wears out, it will have to be dug up and fixed or replaced, but that is rare and would be a major project.