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Author’s Note: These articles are intended as general reference only. The information presented represents my perspective gained from experience as a water gardener and as a business owner. The views expressed here are also influenced by the conditions found in the Midwest and may not be as applicable in other geographic regions.

 Water Garden and Pond

by Joel Police
New Haven, Indiana USA
Photos by Lincoln Soule, Florida USA
Click to enlarge

Often overlooked in the design phase, lighting adds beauty, enjoyment and functionality to your pond. While many beginners omit lighting, it does help to think about lighting that could be added later if not included initially. At least design the infrastructure for future lighting.

Before discussing the specifics of lighting, let's start with a few helpful pointers. First, learn from a nighttime visit with friends or family members to see their illuminated water garden or water feature. You may want to plan a more comprehensive landscape lighting plan of which pond lighting will be one part. If you already have a landscape lighting system, consider similar fixtures and light types for your new water feature to seamlessly integrate the entire landscape. On the other hand, if no lighting currently exists, will your pond stick out being the only illuminated portion of the landscape?

Even if you never plan to spend time outside at night enjoying your pond, the views from inside your house often justify adding lighting. If your installation is visible from the street or other well-trafficked areas, consider lighting to draw attention to your creation.

Finally, consult a professional electrician about mixing water and electricity. Verify that your existing circuitry and outlets are approved for both above ground and underwater lighting. Tell the electrician of your plans for lighting even if it will be added in the future. Then circuits can be designed for all possible needs instead of having to rework them later.

Now let's consider the types of uses decorative lighting offers. In the outdoor environment, decorative lighting (landscape lighting) breaks down into two categories: landscape (dry or wet) and underwater (submerged) lighting. Our focus is landscape lighting for wet locations and underwater lighting.

A lighting fixture (housing that includes the electrical structure that holds the bulb) approved for wet locations is sometimes referred to as "water safe". Water safe fixtures resist rain, mist, splashing, irrigation or other sources of water exposure but are not approved for use underwater. "Waterproof" fixtures have sealed construction that prevents water from entering them. This makes them safe for underwater use, but their heat precludes them from use out of water because of fire risk. Always verify that your lights meet all applicable codes, regulations and proper installation procedures.

Next, let's break decorative lighting into categories depending on the amount of power the lights need. The two basic categories for the decorative lighting market are line voltage (120 volts or higher) and low voltage (15 volts or lower). The low voltage category divides into subcategories including incandescent, LED, fiber optic and solar.

For our conversation, use line voltage lighting as landscape lighting in wet locations or underwater lighting. However, due to safety concerns, underwater line voltage lighting involves the use of transformers to lower them to12 volts. Therefore, let's just address line voltage in regards to wet locations. 

Line Voltage

Once the predominant type of decorative lighting, line voltage lighting most often occurs when illuminating large areas or when great distances exist between the fixture and the object being lit. Because of the higher voltage, the lights use a higher wattage than low voltage lights. Large floodlights and spotlights are good examples of line voltage lighting; anyone who has witnessed Niagara Falls illuminated at night has experienced a prime display of line voltage lighting.

Given its performance advantages for large jobs, what makes line voltage lighting a good choice for smaller applications? First, convenience makes it a likely choice. If you already have an electrician on site running a service for your water feature, it may be very cost effective to add service for lighting at the same time. In wet locations, this ensures all wiring is enclosed in conduit to add an extra safety layer from both water and accidental damage with a shovel, spade, etc.

Another reason to choose line voltage lighting is cost. Line voltage fixtures tend to be less expensive than low voltage fixtures. Their standard incandescent bulbs are readily available at hardware or big box stores. Because line voltage fixtures typically produce more light, it takes fewer fixtures to handle the job, helping to drive down the initial cost. Since seasonal accent lighting can be added simply by changing the color of the bulbs, line voltage fixtures serve multiple functions, eliminating the need to use special holiday fixtures.

As lighting technology evolves, line voltage is falling out of favor for most homeowner applications. Line voltage installations usually require a licensed electrician. With higher wattage bulbs, line voltage lights consume more power than their low voltage counterparts do. Finally, line voltage fixtures suffer from being bulky in order to house large bulbs. Their large size makes hiding or integrating the fixtures into the landscape more difficult. 

Low Voltage Incandescent

While very similar in nature to line voltage lighting, low voltage incandescent lighting differs in both the amount of power used and how that power is generated. A low voltage incandescent system consists of a transformer drawing power from a GFCI (ground-fault circuit interrupter) outlet, fixtures fitted with an incandescent bulb and wire connecting the fixtures to the transformer. Drawing 15 volts or less, they consume significantly less power and provide extra safety compared to line voltage lighting. While any electrical current can be dangerous in wet or underwater applications, low voltage systems minimize the risk and have become the industry standard for underwater installations.

Another obvious difference between line voltage and low voltage incandescent systems is the fixtures and bulbs themselves. Low voltage fixtures feature small bulbs permitting much smaller fixtures. This smaller size allows for much more decorative and artistic looking fixtures easily incorporated into the landscaping. Small underwater fixtures also make dramatic lighting effects without detracting from the pond or water feature beauty during the day.

Low voltage incandescent fixtures approved for underwater use have been available for decades. Typically they utilize a gasket or seal in conjunction with a glass lenses and a screw-on cover. The waterproof power wire and properly installed cover make the entire unit safe for immersion. Remember however that the junction between the wiring for the underwater fixture and the supply wire from the transformer must be above ground and away from the pond.

Bulb choices for low voltage incandescent fixtures include halogen, xenon and metal halide, each offering its own mix of color and intensity. Any type bulb does the job, but it is important to select the right wattage and spacing for the fixtures to ensure an aesthetically pleasing effect. Bulb wattage and number of fixtures in the lighting plan determine the next component of the system.

The heart of any low voltage system, the transformer converts household 110 volts into low voltage current for wet or underwater rated fixture. Always verify that your transformer is approved for wet and/or underwater applications. Most transformers are only approved for dry location use. If the store or supplier cannot properly document a transformer's approved uses, shop elsewhere.

Transformers come in a dizzying range of sizes, wattages, coil types, case constructions and available options. Focus on the wattage and options needed. Purchase the best quality transformer your budget allows, which pays for itself with a longer life and more efficient operation. Again, make sure you pick a transformer approved for wet and/or underwater light fixtures.

A transformer is measured in watts; a small transformer for a few fixtures may be in the 100-watt range. High-end professional models routinely run 600 watts or more. Your lighting plan should determine how many fixtures to use and the wattage for each bulb. Add the wattage of all your bulbs and multiply that number by 115% to find your total lighting load (# of bulbs x wattage of each bulb x 1.15 = wattage of transformer). The additional 15% wattage factored in by this formula accounts for the voltage consumed to send power over the length of the wires connecting the fixtures to the transformer.

If you might add more lights later, consider a transformer that can handle future needs also. It is cost effective to buy one transformer to run your entire system, both present and future, than to buy more transformers as you add lights. Alternatively, purchase one transformer specifically rated for your pond lights and then add a second transformer for all other dry location low voltage lighting. 

Finally, choose between transformers that use timers or photocells to turn the lights on and off. Most better-quality units have programmable digital timers far better than the old "wheel and peg" timer systems on budget models. Photocell systems are a nice choice for those who don't like to change timers as seasons change. One downside of photocell units is that they run from sundown to sunrise, depending on darkness to turn them on and light to turn them off. Alternately, opt for a combination of a timer and a photocell if you want to shut off the system at a predetermined time.

One mistake to avoid during the installation phase of underwater incandescent fixtures is improper placement. Far too often installers place fixtures under a pile of rocks on the pond bottom with no slack in the wire, requiring the pond be drained or the rockwork be torn up when bulbs need changing. Avoid this by leaving wire equal to the pond depth where each fixture is located. Coil the extra cable and place a rock on top of it. When bulbs need replacing, lift the rock and bring the fixture to the surface so you can open it out of the water. Nothing is more frustrating than a lighting system rendered useless by burned out bulbs that cannot be replaced without a major disruption to the entire pond or water feature.

Compared to incandescent line voltage systems, low voltage incandescent lights offer many advantages -- lower initial cost, lower energy consumption, easier installation, greater variety of fixtures and safer applications. However, some drawbacks exist. Because they put out less light than line voltage bulbs, more fixtures are needed to supply the same amount of light. The transformer also adds cost and maintenance over line voltage systems (underwater systems not withstanding). Finally, as low cost suppliers flood the market with low voltage incandescent fixtures, quality has become a major issue. Cheap plastic fixtures damage easily and fail to handle the more stressful conditions in the pond environment.

If you use incandescent low voltage fixtures, seek out a quality brand and avoid plastic units. Brass or stainless underwater fixtures are superior to plastic units but also cost much more. While some quality units with plastic housings are available, most of the early designs leak over time, which ends up burning out the bulb and even damaging the bulb socket. I suggest avoiding underwater fixtures if you cannot budget for better quality units. Why waste money on a product that only lasts a short time before failing? My experiences with underwater incandescent units included in kits and entry-level installations usually involve their removal and/or replacement with better quality units.  

Low Voltage LED

While incandescent bulbs represent the tried and true in low voltage lighting, LED (Light Emitting Diodes) systems signify a changing of the guard. LED technology involves the use of tiny diodes that require very small amounts of energy to produce light. Since they use no filament, almost all energy consumed goes toward producing light instead of heat. In contrast, most incandescent bulbs use 80% or more of the consumed energy to produce heat and the remaining amount actually provides light.

For a long time LEDs suffered from reliability issues and the stigma of the bluish light they produced. Today's LED units produce light almost imperceptible from an incandescent bulb and are extremely long lasting. Many of the newer LED units come with life spans of up to 50,000 hours (13 ½ years of use if operated 10 hours a day) with no bulbs ever to change. Yet the best feature of LED lights is the extremely low amount of power they use.

According to Kichler Lighting, LED lights consume approximately 75% less power than incandescent units for the same amount of light output. Even if you only have a few lights in your system, this amounts to a sizeable savings over their life span. Moreover, LED systems use a smaller wattage transformer. To illustrate the difference between the two light types, consider that typical underwater LED fixtures use about 4 watts of power while standard incandescent bulbs consume 20 watts.

Besides the power savings benefit, the nature of LED construction makes them well suited for wet and underwater uses. With are no bulbs to change, LED fixtures typically come in a permanently sealed housing. This makes them ideal for wet and underwater locations (always check for approval for use in wet and/or underwater locations with the proper transformer). Sealed construction means you can install underwater lights in a permanent location with no worries about leaving extra cable or making provisions to change bulbs. However, make them accessible in order to clean the lenses when you do your regular pond maintenance.

As amazing as LED units are, the big knock against them is price and selection. The number of fixtures available is limited as lighting manufacturers begin to switch over from incandescent to LED production. Typically LED lights cost from 25% to 50% more than incandescent units, but you must look at the cost over the life of the system to see a true picture of what it will cost. When selecting LED lights, go with a trusted manufacturer. Since LED lights are relatively new and consumers may be unfamiliar with them, low quality products may be hard to distinguish from higher quality units. Big box store stress low price systems. Professional grade products reduce your chances of disappointment. 

Fiber Optic

Another emerging trend in pond lighting is fiber optic lighting. Known best for phone and cable transmission, fiber optic technology is making inroads into the home landscaping market. Only a few manufacturers produce off-the-shelf and customized fiber optic systems for all types outdoor home lighting, so the selection is limited. However, because the products are so adaptable to a wide array of applications, fiber optic lighting deserves serious consideration for your project.

Fiber optic systems for ponds and water features work on a very simple principle. An illuminator houses one light bulb as the light source for a number of attached cables. The end of each cable projects the light, allowing it to be placed almost anywhere given the small cable size. Recent cable design improvements increase the light intensity and spread, bringing fiber optic lights into the same performance range as incandescent and LED units. Installation is a breeze. They need no wiring or connections other than plugging in one cable harness into the illuminator.

The major advantage of a fiber optic system stems from having no electrical components in or under water. The illuminator, its only electrical component, rests a safe distance from wet and underwater locations. Another benefit includes the ability to introduce color via a color wheel. Most systems include a means of fixing one color or changing colors by a controller. Add in a remote control and the setup gives you unique flexibility. Moreover, with only one bulb in the entire system, energy consumption is extremely low and you only have to worry about changing one bulb every few years.

Because fiber optic technology is still evolving, the cost is higher than other lighting choices. Again, however, consider cost as a function over the system's lifetime. When looking at the initial investment, budget more for fiber optic lights than other systems. Currently the systems are best suited for underwater applications, but standard wet and dry landscape fixtures are starting to appear. However, other types of low voltage lighting might better handle spot and flood lighting. 


The final type of lighting worth mentioning is solar powered lighting. Since pond owners tend to be very environmentally conscious, solar lighting is always a welcome addition to the pond environment. Often used as a means to power low voltage and LED fixtures, solar power is gaining traction in the lighting world. Primarily functioning in wet locations, solar powered lighting offers homeowners a free source of renewable energy that obviously makes solar the clear expense-of-operation winner compared to other systems.

Along with an extremely low operating cost, solar lights for wet locations are simple to install. No wiring is involved! Each light is a self-contained unit with its own power source. This gives great flexibility when placing the lights in the landscape. The low operating voltage also makes them a safe alternative around wet areas like ponds and water features.

However, solar today has more negatives than its positives can offset. Besides a limited selection of fixtures and lighting units, solar lights depend on steady sun exposure to deliver a dependable light source each night. The efficiency of the solar cells and the storage bank greatly affect how bright and how long the light lasts each night. Location can also be a challenge for solar units; shaded areas reduce the amount of light the cells capture.

Like fiber optic lights, solar lighting is not the first option for flood or spot lighting since the wattage of solar powered lights is frequently very low. Few underwater solar lights are available today due to the challenge of connecting a wire from a solar collector panel to the underwater fixture. Pond owners then have to find a way to incorporate or "hide" these small solar panels in the landscape. Finally, solar fixtures tend to be larger than other low voltage fixtures since they must include a fair amount of surface area for the solar collector panel.

Despite the obstacles solar lighting currently faces, it clearly represents a long-term solution for the future. Most likely we will see a combination of solar power with LED or fiber optic fixtures to bundle the best of both. Regardless of how solar, LED and fiber optic technology advance, it has become clear that incandescent lighting is on the way out. While some countries like Canada already regulate the use of incandescent bulbs (Christmas lighting is primarily LED based), it appears to be just a matter of time before landscape lighting goes completely green and incandescent bulbs fade from the market.

In summary, plan ahead by contemplating present and future lighting needs. A well-planned lighting design will save time and money when turning your pond or water feature into a sparkling jewel at night. While the technical aspects of lighting may be confusing, you can always turn to a trusted pond or water garden contractor or electrician for advice. In the end, preparing for all possibilities (even if you forgo lighting at first) will make for a much more enjoyable installation instead of scrambling to add lights later on.   

Introduction to this multi-part series
Your Water Garden

< Water Features, Water Gardens, and Specialized Ponds
< Planning: Location, Design, Action
< Materials and Components for your Pond
< Filtration Systems for Water Gardens and Koi Ponds
< Pumps

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