Most flood damage in residential homes does not happen because the homeowner did not own flood protection. It happens because the protection was in the wrong place — in the garage, in the back of a closet, in a storage unit across town — when water started rising.
StormBags are designed to deploy fast: each one-pound dry bag expands to roughly 33 pounds of flood protection on contact with fresh water in three to five minutes. But that speed only matters if you can grab them, walk them to the right entry point, and lay them down before the first inch of water reaches your slab. That is a staging problem, not a product problem.
This guide walks through the most common entry points for residential flooding, where to stage StormBags for each one, and how many to keep on hand at each location. The goal is to make deployment fast enough that you can do it after a flash flood watch is issued — not after the water arrives.
How residential floodwater actually gets into a house
Before deciding where to stage protection, it helps to think clearly about how water enters a home. Floodwater is opportunistic. It finds the lowest gap, the weakest seal, the most direct path from outside grade to inside floor. In a typical single-family home, those entry points usually rank in this order:
- Garage door — almost always the largest opening at the lowest elevation, and most garage doors are not sealed against water
- Front and side entry doors at grade — especially homes with a step-down from the front walk to the foyer
- Basement window wells — the classic backup-flooding path in homes with finished basements
- Patio sliders and french doors — long horizontal seals are difficult to defend, and the track collects debris
- Sump pump pit and floor drains — not external entry, but the path floodwater takes after the perimeter is breached
- Crawl space vents — in homes built on piers or short stem walls
You do not need to defend all of these. You need to defend the ones that apply to your house, and you need to know which one to defend first if you only have a few minutes.
The garage door: where most homes need the most protection
The garage door is the single highest-risk entry point in most homes for one simple reason: it is wide, it sits at or near grade, and the bottom seal is engineered to stop drafts and rodents, not water. A standard double garage door is 16 feet wide. To build a continuous six-inch-high barrier across that opening once water is on the driveway, you need roughly 15 to 20 hydrated StormBags laid in a slightly overlapping running-bond pattern.
Where to stage: Inside the garage, against the wall closest to the door, in a labeled plastic bin or on a low shelf. Not in the attic. Not in a closet at the back of the house. The bags need to be within arm’s reach of the door they protect.
How many: A 25-pack of StormBags staged at the garage covers a typical double-door opening with enough surplus for a second course in heavy flooding.
If your garage has both a vehicle door and a side service door, stage a few additional bags near the service door — it is often forgotten and can be the first failure point because the seal is older and the threshold lower.
Front and side entry doors
For exterior doors at grade, the question is not whether the door itself is watertight — most are not — but how quickly you can lay a two-bag-high barrier across the threshold before water builds up on the porch.
Where to stage: A small bin (six to ten bags) in the entry closet, mudroom, or pantry — whatever is closest to the door without blocking the swing.
How many: Four to six hydrated bags will cover a standard 36-inch door at two courses high. Stage six to ten dry bags so you have margin for sealing both sides of a double-leaf entry door or for adding height if the storm intensifies.
If you have a covered porch, this is also where storm-surge or wind-driven rain can pool. A second small bin near the front door is cheap insurance.
Basement window wells
Window wells are deceptive. They look protected because they are below grade and partially covered. In a flash flood, they fill from the top down with surface runoff and saturate the surrounding soil — and the basement window is the failure point.
Where to stage: In the basement itself, in a clearly labeled bin near the utility area. The bags need to come up the stairs and out the back door to the exterior of each window well — do not store them inside the well or outside in the elements.
How many: Two to three hydrated bags per window well, laid in front of the well opening on the lawn side to deflect surface runoff. For a typical home with three basement windows, plan on eight to ten staged bags.
If your basement has had water in the past — even minor seepage — this is the area to over-protect, not under-protect.
Patio doors and french doors
Sliding glass doors and french doors are difficult to defend because the seal runs along a long horizontal track that collects debris and never fully waterproofs even when new. The good news: most patios sit on a small concrete pad that is slightly elevated from the surrounding lawn, so unless the patio itself floods, the door is not the first thing to fail.
Where to stage: In a nearby closet or in the room itself (under a console, behind a piece of furniture). The deployment path is across the floor, then out through the slider track — minimize the distance.
How many: Five to eight bags for a standard six-foot patio slider. Lay them along the outside threshold of the door, not the inside — you want water held off the seal entirely if possible.
Sump pump and floor drain backups
This is not perimeter protection. This is the backstop. If exterior protection fails or if your sump pump loses power during the storm (extremely common), water comes up through the basement floor drain or out of the sump pit. A small ring of hydrated StormBags around the perimeter of the sump pit and floor drains creates a temporary dam that buys you time to get critical items off the floor.
Where to stage: In the same basement bin as your window well bags — you will be using them in the same place.
How many: Two to four bags per drain or pit, added to your basement allocation.
The 5-minute rule
Here is the test for whether your staging plan is good enough: from the moment you hear a flash flood warning on your phone, can you have your top three protection points covered in five minutes or less?
For most homes, that means:
- Bags for the garage door are inside the garage
- Bags for the front door are within ten feet of the front door
- Bags for the basement are in the basement, not in the attic or a back closet
If the answer is no — if you have to walk across the house, open a storage unit, or dig through holiday decorations to find your flood protection — restage now, before the next storm watch.
A note on water source for hydration
StormBags hydrate with fresh water. In a storm, the rain itself does most of the work — the bags activate from rainfall or surface runoff as soon as they are laid down. For pre-deployment in a dry environment (sealing a leak indoors, for example), use a garden hose, a bathtub, or any clean tap source. Do not try to hydrate them in salt water; they will not absorb properly. Once hydrated with fresh water, they will repel salt water if a coastal storm surge follows.
How many bags should you actually own?
A reasonable starter set for a single-family home with a garage and a finished basement:
- 25-pack at the garage (primary deployment point)
- 10-pack inside the home (split between front door entry closet and the basement)
That gives you roughly 35 bags total, enough to defend three to four entry points at two courses high, with surplus for emergencies. For homes in repeat-flood zones, hurricane-prone coastal counties, or areas downstream of recent burn scars, double the staging at each location.
For a more detailed breakdown of bag counts based on your specific home, see our companion guide: How Many Sandbags Do I Need to Protect My House?
One more thing: label your bins
This sounds trivial. It is not. When a flash flood watch goes up at 2 a.m. and you are operating on adrenaline, the worst time to be hunting through unmarked plastic bins is in the dark with rain hitting the roof. Label every staging bin in large letters: FLOOD — STORMBAGS — [LOCATION]. Take five minutes today. It might be the most useful five minutes of preparation you do.
For real-time flood alerts in your area, including watches, warnings, and advisories from the National Weather Service, visit our Flood Watch tool. It is free, no login required, and updates every few minutes.
