The word oasis calls forth images of a life-giving watering hole in the middle of a parched desert. No wonder people are fond of installing water features in their own backyard oases. But if the prime objective is to enjoy the hypnotic effects of running water and not to take care of a sensitive little ecosystem, a koi pond with lily pads and ferns is the wrong choice. Instead, low-maintenance water features can help homeowners conserve water, save money for design and installation and spend more time enjoying their oases instead of scrubbing and repairing. Off-the-shelf options The simplest solutions are accent pieces that can be purchased right off the shelf at garden centers and simply plugged in. Voilà – instant Zen! Often made of resin for portability, these bubbling urns and decorative fountains require no plumbing. An electric pump recycles the water. The only maintenance needs are keeping the pump filter clean, removing debris like fallen leaves, and occasionally replacing water lost to evaporation and splash-out.If algae start to appear, "on a hot, sunny day, unplug the fountain and let the sun bake off the algae," said Matt Septeowski, owner of Along the Waters' Edge, Lombard, Ill. Disappearing act For a more natural look, consider a pondless waterfall, sometimes called a "vanishing water" feature. A vanishing water feature is a self-contained system that pumps water back to the top of the waterfall in a continuous cycle without allowing water to collect at the bottom. "These solve a lot of problems that a pooling system might have," such as the pond-and-waterfall kits sold at garden centers, said Ken Box, owner of Somerset Gardens, Edmonds, Wash. Where there is pooling water, "The sunlight hits it and you get algae growth," he explained. And ponds of a certain depth create a drowning hazard and trigger code requirements like fencing. This type of system requires about the same maintenance as a simple fountain but makes a bigger splash, so to speak, as a focal point. The unit can be equipped with an auto-fill feature so it doesn't need to be topped off. "You might have to scrub the waterfall [spillway] with a brush occasionally," said Chris Kane, co-owner of Kane Bros. Inc., an aquatic environment firm in Homer Glen, Ill. When not to DIY In-ground, freeform water features can be low-maintenance if a professional contractor does the installation, but as a DIY project, the design and installation are challenging. First, the land needs to be excavated to form the desired shape and lined with a membrane liner. Because flexible liners can spring leaks, Box recommended "sandwiching" them between protective layers of fabric. Next, a rebar grid is used to form a rigid mold for the concrete base, which is then hidden from view with rocks and spillways. Fishing for trouble Adding fish to the equation complicates matters further. "I tend to try to steer people away from fish ponds," Box said. "I ask, 'Do you really want fish? Is that your goal?' Usually, it turns out what they want is the sound of running water and to attract birds." Fish ponds have been known to attract unwanted critters. "I put in a little pond at my house and all the koi were eaten," Box said. "I was on the raccoons' regular route." A fish pond or water garden requires monitoring and ongoing maintenance because it's a living system. "You're feeding fish and the fish are doing their business in there, which brings up the nitrogen level in the water, which promotes plant growth," Box said. "You get into a lot of cleaning and filtration issues." If a person is intent on having a full-fledged ecosystem in the backyard, Septeowski said, "It needs to be properly designed and constructed with the right amount of fish and plants, and then it becomes stable and self-sustaining." Achieving the optimal balance requires more patience than tinkering. "By the third year, everything's taking care of itself," he said. According to Septeowski, by then, it tends to take less time to maintain the pond than to cut the grass it's replacing. That means the pond is healthy, not constantly crystal-clear, he added. "A lot of factors affect water quality, from temperature fluctuations to rainfall," he said. "There are a lot of chemicals you can add, but I say stay away from those and let nature take care of it. A pond can be pea green one day and perfectly clear the next if you leave it alone and let it balance out and stabilize itself."