Your Router, Your Modem and Your Backup Drive All Live in the Wettest Corner of the House

Ask anyone what threatens the electronics in their house and you will hear about power. Surges, brownouts, a lightning strike, the moment the grid comes back harder than it went away. It is a real threat, we have written about it repeatedly, and almost every house now has at least a power strip with a joule rating printed on the box.

The other threat is water, and virtually nobody has thought about it, because the picture in everyone's head is a flood — a river, an evacuation, a news helicopter. That is not what this is. The event that takes out home technology is a supply hose behind a washing machine, a water heater at the end of its life, a roof valley that leaks for one week a year, or a slab leak that finds the low point of the room. It is small, it is boring, it is very common, and it lands squarely on the one corner of the house where — for reasons set out in federal regulation — all of your networking equipment was always going to end up.

Why every wire in your house converges on the same bad spot

This is not an accident of how your installer felt that day. For telephone wiring the location is written down. 47 CFR 68.105(c) says that for a single-unit premises, "the demarcation point shall be a point within 30 cm (12 in) of the protector or, where there is no protector, within 30 cm (12 in) of where the telephone wire enters the customer's premises, or as close thereto as practicable." For buildings with multiple units the same section defines a "minimum point of entry" as "either the closest practicable point to where the wiring crosses a property line or the closest practicable point to where the wiring enters a multiunit building or buildings."

That rule is about the phone network specifically, and your fibre or cable provider is not bound by it. In practice they all follow the same logic anyway, because the cheapest place to terminate a service is exactly where it comes out of the ground or off the pole. So the box with your provider's name on it — the NID, the ONT, the cable ground block — is bolted to an exterior wall, or just inside it, at the lowest practical height.

Then everything else followed it there, because that is where the wire is. The modem went next to the ONT. The router went next to the modem. The little unmanaged switch went next to the router. The surge strip went on the floor underneath all of them because that is where the outlet is. If your house was built or rewired in the last twenty years, there is a good chance all of it is inside a recessed low-voltage panel in a wall. And at some point somebody set an external backup drive on the shelf above the whole stack, because that shelf was free.

In a Southern California house that corner is almost always the garage. We build on slabs and we do not have basements, so the garage is where the water heater goes, where the washer and dryer go, where the main panel goes, and where the low-voltage gear goes. Four of those five things are within a few feet of each other in a very large number of the houses we work in. Three of them involve water under pressure or a tank of it, and the fourth is your entire internet connection sitting on a concrete floor.

How ordinary this actually is

The insurance numbers are the useful reframe here, because they describe frequency rather than drama. The Insurance Information Institute publishes claim data from ISO, a Verisk Analytics business. Over the five years 2018 through 2022, water damage and freezing produced 1.61 claims per 100 house-years, with an average of $13,954 paid per claim. In the same period 5.8 percent of insured homes had a claim of any kind, and water damage and freezing was the second most frequent cause behind wind and hail, affecting 1.6 percent of insured homes.

Round that off and roughly one insured home in sixty files a water claim in a given year. That is not a disaster-movie number. That is a normal thing that happens to normal houses, on a timescale where most people will see one at some address they live at. And the claim total is for the building and the contents — nobody is itemising the modem.

Why we are writing this in August

Because the forecast currently says to. NOAA's Climate Prediction Center issued its monthly ENSO Diagnostic Discussion on August 13, 2026, and the synopsis reads: "El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27." For October through December 2026 the discussion puts "a 69% chance of a historic event that would exceed the strength of previous El Niño events dating back to 1950."

Read the caveat that CPC attaches to it as well, because it matters: "With an event of this magnitude, the chances of experiencing impacts consistent with El Niño are larger, but they are not guaranteed." A strong El Niño tilts the odds toward a wet winter in Southern California. It does not promise one, and anyone telling you otherwise is selling something.

That is still enough to justify twenty minutes in the garage now rather than in January. The jobs in this article are cheap, they are permanent, and every one of them is easier to do on a dry Saturday than during the week the roof is leaking. If the winter turns out mild, you have lost twenty minutes and gained a modem that is no longer on the floor.

The part that will surprise you: after water, the industry says replace, not dry

Search for what to do with a wet router and you will get a remarkably consistent answer: unplug it, leave it 48 hours, maybe use a hair dryer or put it in the sun, then hit the reset button and see. That advice is everywhere, and for equipment that plugs into mains power it is wrong in a way that matters.

The National Electrical Manufacturers Association publishes a free guide called "Evaluating Water-Damaged Electrical Equipment" — NEMA GD 1, in its 2016 edition. It exists so that after a flood, an electrician or an inspector has a per-category answer to "can this be saved?" It is a table with two columns: replace the equipment, or it may be reconditioned after contacting the manufacturer.

The categories relevant to a household technology shelf are all in the replace column. Surge-protective devices — the guide names "transient voltage surge suppressors, surge arresters, lightning arresters" — replace. Wiring devices, meaning "switches, receptacles, dimmers, etc." — replace. Batteries — replace. Uninterruptible power supply — replace. "Signaling, protection, and communications systems" — replace. And "wire or cable listed for dry locations (such as NM-B)" — replace.

The section behind that last group is worth quoting directly. Section 4.11 covers electronic products including communication systems, and says that water can cause "corrosion of components of the system, shorting or alteration of printed circuits, or alteration of circuit characteristics," concluding: "Where such systems are damaged by water, replace components of these systems or return the equipment to the manufacturer for appropriate cleaning, recalibration, and testing." The guide also warns generally that "electrical equipment exposed to water can be extremely hazardous if reenergized without performing a proper evaluation and taking necessary actions," and on cable specifically that "wire and cable listed for only dry locations may become a shock hazard when energized after being exposed to water."

None of that is written about routers. It is written about building electrical equipment, and NEMA is explicit that the evaluation is a job for qualified people, not a homeowner with a multimeter. But the mechanism does not care what the box is for, and the direction of the advice is unmistakable: the industry that manufactures this equipment does not think drying it out and switching it on is the plan.

The surge strip is the part that stings

We have spent years telling people to buy a decent surge protector and a battery backup. Both are on that replace list, and there is a certain irony in it: the two devices whose entire job is to protect everything else are the two you cannot keep.

It makes sense once you look at what they are. A surge protector works by sacrificing components inside itself to divert energy away from your equipment, so its protective capability is finite and invisible — there is no way to look at one and know what it has left. Add corrosion on those internal parts and you have a device that still lights its green LED, still passes power, and no longer does the one thing you bought it for. A battery backup is worse, because it is a surge protector with a sealed lead-acid battery in it, and NEMA puts batteries in the replace column too: contacts and cans corrode, and the guide notes that long exposure can let a battery rust through and release what is inside it.

So if the shelf got wet, the replacement list starts with the protection hardware. It is genuinely annoying and it is not expensive relative to what it is guarding.

The one thing you must not dry: the drive

Everything above says do not power it on, and the drive is the same on that point — more emphatically. But the drive is the exception on drying, and this is the single most useful thing in this article, because the instinct is exactly backwards.

If an external hard drive has been wet, do not dry it. Do not put it in the sun, do not put a hair dryer on it, do not put it in rice. Put it in a sealed plastic bag, wet, and take it to a data recovery lab. That advice is not ours originally — it is close to unanimous among the labs that do this work commercially, and their reasoning is consistent and easy to check: water on its own rarely destroys what is written on the platters. What destroys it is electricity meeting moisture, and then corrosion, which starts within hours and accelerates as things dry unevenly and leave mineral deposits on the heads and the contacts. Keeping the drive wet and sealed buys the lab time to open it under controlled conditions.

The corollary is the one people get wrong under stress: the worst possible move is to plug it in "just to see if it still works." If it does spin up, you have very likely just converted a recoverable drive into an unrecoverable one, and you will not find that out until later. The same instinct is why we wrote a whole separate article about laptops and spills — the wait-before-you-power-it-on rule is the same rule, and it is broken for the same reason.

What you can move, and what you genuinely cannot

The box with the provider's logo on it is not yours. The ONT, the NID, the cable ground block and the drop coming into it belong to the company, and its position is either fixed by the rule quoted at the top of this article or fixed by the fact that the fibre has no slack in it. Do not unbolt it, do not extend it yourself, and do not open it. If it needs to move, that is a service call to the provider, and they will sometimes do it.

Everything on your side of that box is fair game, and that is nearly all of it. The modem, the router, the switch, the access point, the power strip and the drive are all yours to relocate, and none of them needs to be where it is. The single highest-value change is also the least glamorous: get it off the floor. A shelf at chest height on the wall costs about twenty dollars and defeats the entire category of a few inches of water across a slab, which is what the overwhelming majority of these events actually look like.

Second: get it off the wall shared with the laundry, and out from under anything plumbed. If your low-voltage panel is recessed into the wall directly behind a washing machine or below an upstairs bathroom, that is worth knowing even if you do nothing about it, because it tells you where to look first when something goes offline in the middle of a rainstorm.

Third: mind the outlet, not just the box. A surge strip lying on a concrete floor is a wiring device and a protective device sitting in the exact place water collects. Mount it or hang it. Concrete slabs also wick moisture upward for years without anything dramatic happening, which is its own slow version of this problem.

The backup drive should not be in the same room as the computer

This is where the water argument and the backup argument meet, and it is the reason we think this topic is worth a whole article rather than a paragraph.

The 3-2-1 rule — three copies, on two kinds of media, one of them offsite — usually gets explained as a filing discipline. It is not. It is a statement about geography. The reason the third copy goes somewhere else is that copies stored together share a failure. A drive can fail on its own schedule, but water, fire and theft arrive at a location, and they take everything on the shelf.

So the question to ask about your backup is not "do I have one?" It is "what single event reaches both copies?" If the computer is on the desk and the backup drive is beside it, the answer is a roof leak over that room. If the computer is in the office and the drive is in the garage with the network gear, the answer is the water heater. If both live in the low-voltage panel, one bad hose gets the lot.

The fix is free. Move the drive to a different room, ideally a different floor, ideally not the lowest one. Then add something that is not in the building at all — a cloud backup, or a second drive that lives at work or at a relative's house and gets swapped every so often. That is not a bigger budget than you already have; it is the same drives in different places.

If it has already happened: the first hour

Power first. Kill the circuit at the breaker before you reach into a wet area, and do not stand in water to do it. NEMA's warning about re-energising equipment applies just as much to the equipment that is still switched on right now. If you cannot get to the panel safely, that is a call to an electrician, not a job to improvise.

Then photograph everything before you move a single item. Wide shots and close shots, with the water still visible and the gear where it sits. If any of this ends up on a claim, the photograph taken before the cleanup is worth more than every receipt you can dig up afterwards, and it costs thirty seconds.

Then sort what you have into three piles, because they get three different treatments. Anything with data on it that you care about — external drives, a NAS, the computer itself — goes into a sealed bag if it is wet, unpowered, untouched, and off to a recovery lab. Anything that plugs into mains power and got wet — surge strips, the battery backup, chargers, the power supply — goes in the replace pile, on the guidance above. And anything with the provider's name on it gets reported to the provider rather than dried out, because it is their asset and their replacement.

One thing not to do: do not test anything. The urge to plug the router back in to find out whether you got lucky is very strong and it is the move that converts a maybe into a definitely.

The small-business version, which is worse

In a small office the same convergence happens, only tighter and with more at stake. The rack or the wall board goes in a back room, and the back room is chosen because nobody wanted it — which very often means it is the room with the water heater in it, or the one under the upstairs restroom, or the closet with the mop sink. We have opened a lot of these closets.

The specific exposure is that the server or NAS, the switch that everything is plugged into, the router, the surge strip and — nearly always — the local backup target are all inside the same four feet of wall. That is not three copies of the data. It is one copy and two more copies of the same room. For any business where a day offline is a real cost, the offsite copy stops being good practice and starts being the entire plan, and the honest test is the same as at home: name the single event that reaches all of it, and if you can name one easily, fix that.

The other small-business specific: an alarm panel, a phone system, or a card reader sitting on that same board is in NEMA's "signaling, protection, and communications systems" category, and its failure mode after water is silence. It will not tell you it stopped working.

The twenty-minute walk

Do this once and you never have to think about it again. Find where the service enters — look for the box with the provider's name, usually on an exterior wall, in the garage, or in a recessed panel in a hallway. Note what is plumbed within about six feet of it in any direction, including above it, and remember that a second-floor laundry or bathroom counts as "above."

Then: is anything on the floor? Move it to a shelf. Is the power strip on the slab? Mount it. Is there an external drive anywhere in that stack? Move it to another room. Is your only backup in the same room as the computer it backs up? Fix that today; it is the cheapest item on the list. And if the answer to "where is my offsite copy" is "I do not have one," that is the thing to solve before the winter, not the modem shelf.

None of this requires tools beyond a drill and a shelf bracket, and none of it is urgent in the way a broken thing is urgent — which is exactly why it never gets done.

How we can help

We do this as part of ordinary network and backup work: looking at where your equipment actually lives, getting it off the floor and out of the wet corner, tidying the run so it can be moved at all, and setting up a backup that genuinely has a copy somewhere else rather than three copies on one shelf. For a small business we will happily open the back closet and tell you honestly what is in there and what would happen to it.

And if something has already got wet, call before you plug anything in. The order of operations in the hour after matters more than anything you can do the next day — especially for a drive, where the difference between a sealed bag and a hopeful power-on is often the difference between recovering the data and not.