The Short Answer: It depends on which generator you own. A standby unit is sealed in its own weatherproof housing and bolted to a pad outside, so it starts on its own and runs straight through the storm without anyone stepping into the rain. A portable generator is built for outdoor use but not wet conditions: water reaching the outlets, the control panel, or the engine creates an electrocution risk and can cause permanent damage, so it needs a cover or canopy that keeps rain off while leaving the machine plenty of air.
What Water Actually Does to a Generator
A running generator is an internal combustion engine bolted to an electrical device. Water is a problem for both halves, in different ways.
The Shock Hazard
This is the one that hurts people, and its specific to portables. A portable generator produces enough electricity to kill, and its outlets and control panel are the places where that electricity is exposed. Water bridging those contacts, or pooling under a unit while someone reaches for the plug, turns an ordinary machine into a serious electrocution risk. Standing on wet ground while touching a wet generator is how a manageable outage becomes an emergency.
Short Circuits and Fried Electronics
Even when nobody gets hurt, water in the electrical components can cause expensive issues. It can short-circuit the outlets, corrode the terminals, and get into the control panel where the sensors and circuitry live. Inverter generators are especially vulnerable, since their electronics are more sophisticated than those in conventional units and lead to costly repairs when they fail.
Water Inside the Engine
Rain that reaches the air intake gets pulled toward the cylinder. Water in the fuel tank, whether it came in through a loose cap or a splash while refueling, works its way into the fuel system and stops the engine from running properly. Neither problem announces itself immediately, but both shorten the life of the machine.
Corrosion Risk
The slow damage matters too. Even light rain, repeated across a season, leaves moisture sitting on the frame, in the recoil housing, and around the alternator. That moisture will rust and corrode internal components over months. This is the damage that shows up as an engine that will not start next hurricane season.
The Two Shortcuts to Avoid
Both of the obvious solutions are worse than the problem.
Do not move the generator into the garage, the shed, or under the deck. A generator produces carbon monoxide, which has no color and no smell and builds up fast in any enclosed space. An open garage door does not fix this. Carbon monoxide poisoning kills people during storms every single year, and it usually happens because someone was trying to keep their generator dry.
Do not throw a tarp over it. A tarp draped on a running generator traps heat against a machine with an exhaust hot enough to ignite it. It denies the engine the proper ventilation it needs to stay cool. It also holds exhaust fumes right where the unit is breathing. A tarp is a fire waiting to happen, and it does not even keep water out very well.
Every legitimate approach below does the same two things at once: it keeps the rain off, and it leaves the generator plenty of open air.
How to Weatherproof a Portable Generator
Use a Purpose-Built Cover or Canopy
The right generator cover is one designed to be used while the unit is running. Generator tents and canopy-style covers attach to the frame and sit above the machine, shielding it from rain while leaving the sides open. The exhaust stays clear, the air intake stays open, and nothing touches the hot parts.
Larger permanent options exist too. A steel or aluminum generator enclosure, or a small open-sided shelter, gives you a dry area to run the machine in bad weather without confining it. Any of these beats improvising, and the manufacturer will tell you what clearance the unit needs on each side. Read the manual and leave the clearance it specifies on every side.
Get It Off the Wet Ground
Water pools. Driveways slope, grass holds moisture, and a generator sitting in a low spot means that it will be in a puddle by hour three of a storm.
Set the unit on a dry surface with some elevation. Concrete blocks, a raised pad, or a stable platform all work. The goal is that rising water on the ground does not reach the machine. Keep it well away from the house too, with the exhaust aimed away from any door, window, or vent so fumes cannot drift back inside.
Treat the Cords Like Part of the System
An outdoor-rated extension cord is the only kind that belongs anywhere near a wet generator, and it needs undamaged insulation along its whole length. The vulnerable spots are the connections: where cords meet each other or plug into the generator. Those should stay elevated and clear of standing water. Cord covers and simple elevation both help.
If your generator has a GFCI outlet, use it. If it does not, a portable GFCI adapter is a small purchase against a real hazard.
What About Standby Generators?
A standby generator lives outdoors permanently, and it is built for that. The unit ships inside a weather-rated enclosure, typically corrosion-resistant aluminum, engineered to keep rain, snow, and debris away from the engine and the electrical components while still letting the machine breathe and cool. It starts on its own through a transfer switch and runs in heavy rain without anyone stepping outside, which is exactly the point, since the weather that causes the outage is the weather the generator has to work through.
Installation matters here. A standby unit belongs on a level pad raised above the surrounding grade so runoff and standing water stay below it, and it needs the clearance the manufacturer specifies on every side. In a flood-prone spot, pad height is something to discuss with your installer before the concrete gets poured, not after.
Regular maintenance keeps the enclosure doing its job. Seals age, hardware loosens, and debris collects. A yearly inspection catches all of it.
Your Generator Got Soaked. Now What?
If a portable unit has been rained on hard, or worse, if it has been sitting in floodwater, do not start it.
Starting a wet engine can drive water into the cylinder, and a cylinder full of water does not compress. That is how a hydrolocked engine bends a connecting rod, and it is a repair that often costs more than the generator.
Instead:
- Shut the generator down if it is running, and disconnect everything
- Let it dry completely, well beyond the point where it looks dry
- Check the oil. If it looks milky or light brown, water got in, and the oil needs changing before the engine turns over
- Drain fuel that may have taken on water
- Look over the outlets, the control panel, and the wiring for corrosion or damage
- Have a technician inspect it before you use it again
Water damage is not always visible from the outside, so a generator that has been submerged is a service call, not a DIY project. An inspection costs a fraction of a seized-engine repair, and it catches the electrical damage that can shock whoever touches the unit next.
Get Your Generator Storm-Ready with Anderson Power Services
Rain is not a hypothetical in the Southeast. It arrives with the same storms that take the power down, which means the equipment you bought for the outage has to survive the conditions that caused it.
The right setup depends on what you’re protecting and where you live. Anderson Power Services helps you choose between a portable unit and a permanent standby, then handles the harder part of keeping that generator running through the weather that knocks the power out. For a portable one, that means the right cover, placement, and cord setup. For a standby, it means a properly sized unit on a pad above the grade, sealed against rain and serviced every year so the enclosure keeps doing its job.
From there, we cover everything else. As an authorized Generac dealer, we sell and install Generac home, commercial, and industrial generators, plus automatic transfer switches, propane tanks, and portable units. Our factory-trained technicians service Generac, Kohler, and other major brands, and we install EV charging as a ChargePoint dealer. Every job starts with a free on-site or virtual consultation and moves into professional installation, ongoing maintenance, and 24/7/365 remote monitoring through a Peace of Mind Service Plan. Financing is available through Synchrony.
We’ve been veteran-founded and family-based since 1995, serving Georgia, South Carolina, South Alabama, and Florida, with a 4.9-star Google rating across more than 1,000 reviews. Call 770-758-0650 or schedule your free consultation, and we’ll make sure your generator is ready before the next storm.
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