Some under-sink reverse osmosis systems run without electricity, but many include a booster pump or an electronic tank monitor that needs power. If your St. Louis home has low incoming water pressure or an older kitchen, the system maker may list a booster pump as an option. Before you buy or install one, check the electrical side first, because a pump plugged into the wrong place causes more trouble than a slow tank.
Find out whether your system needs power
Read the manual or product sheet for the unit you are considering. Look for a pump, a pressure switch, a monitor, or an electronic faucet light. If the system runs only on incoming pressure, it may need no outlet at all. If it lists a pump, note what kind of plug or circuit it wants, and whether the maker asks for any special protection device.
Look at the outlet under the sink
Many older St. Louis kitchens have no outlet inside the sink cabinet. Some have one, but it may share a circuit with the dishwasher, disposal, or refrigerator. Check these things:
- Is there an outlet inside the cabinet, and is it a grounded three-prong type?
- Does the outlet work when you plug in a lamp?
- Does it have a reset or test button, which suggests protection is already built in?
- Is the outlet damp, cracked, or showing burn marks?
- Is there room in the cabinet for a plug and a cord that pipes will not pinch?
If the outlet is damp, cracked, or scorched, stop there and call a licensed electrician before using it for anything.
Keep water and wiring apart
Water and electricity should never meet. Before you do any work under the sink, shut off the cold supply valve and open the faucet to relieve pressure. Keep the pump, its plug, and any power strip on the cabinet floor, away from the drain area and off the wet deck. Do not run a cord across a path where water might drip. A plug should never sit in a puddle, and a power strip should never be the only protection for a booster pump.
Check your circuit and breaker panel
Look at the breaker panel in your basement or garage and find the breaker that feeds the kitchen outlets. Note which other appliances share that breaker. A booster pump is small, but adding it to a busy kitchen circuit can cause nuisance trips when the dishwasher, microwave, and disposal run together. If you are not sure which breaker feeds the sink, a licensed electrician can trace it for you.
When to call an electrician
Call a licensed electrician if the sink outlet does not exist, if the outlet is old or loose, if you need a new outlet in the cabinet, or if the breaker panel is crowded. Also call if the RO maker asks for a dedicated circuit. Do not run an extension cord from another room to power a pump. Permit and inspection rules vary by municipality, so ask your local building office in St. Louis what applies to your house.
Questions to answer before you buy
- Does the system need power at all?
- Where is the nearest suitable outlet, and is it inside the cabinet or outside it?
- Which breaker feeds that outlet, and what else runs on it?
- Is there space for a pump, a cord, and a drip tray?
- Have you checked the outlet for damage?
Answering these questions first keeps the electrical side of an under-sink RO project simple. When the water side and the power side are both settled, the installation goes more smoothly.