How to Check Internet Availability at an Address (and How to Check Cell Signal Before You Buy)

by Brian Wittman

You can know exactly what internet you'll be able to get at a house before you write the offer, and it takes about twenty minutes at your kitchen table.

Here's the part that trips people up. Every map you can check is a claim, not a fact, and the two big ones are wrong in opposite directions. Broadband coverage is self-reported by the providers themselves. Cell coverage maps are built and validated from vehicles driving on roads, which means they describe your driveway and say nothing about your basement.

Between November 2022 and November 2023, people filed roughly eight million challenges against the federal broadband map. The FCC accepted about four million of them. Providers conceded about half. Two million addresses that were listed as served, weren't.

How do you check internet availability at an address?

Start with the FCC National Broadband Map at broadbandmap.fcc.gov and type in the full street address. It'll show you every provider that reports service there, what technology each one uses, and both the download and upload speeds they advertise. Two things to watch: confirm the address actually appears in capital letters below the search bar, because if it doesn't, the FCC doesn't have your house on file at all. And turn off the default filter that hides anything under 25 Mbps, or you'll see an empty result that isn't empty. Then treat that list as a call list, not an answer.

Why does the map say I have service when I don't?

Because of what "available" is allowed to mean.

Under the federal reporting standard, a provider can report your address as served if it could start service within ten business days of a request, with no charges tied to extending its network. That's it. It's a self-certified claim about what a company believes it could do, submitted by the company, about its own coverage.

It isn't a statement that a line is at your curb.

The Government Accountability Office looked at this in 2025 and found what you'd expect. Providers are the only source of the data. The ten-business-day rule inflates the numbers. Advertised speeds get reported instead of typical speeds, which overstates quality. One group told GAO that providers have a reason to overstate coverage, because a location that looks served is a location a competitor won't bother building to.

Now, none of that makes the map useless. It's the best starting point that exists and it's free. It just answers a narrower question than the one you're asking. You want to know what you can get. The map tells you what somebody claims they'd sell you, which isn't the same question at all.

There's also a lag. Providers report as of June 30 and December 31 each year, with months of processing after that, so what you're looking at describes conditions six to eleven months ago.

Why can a brand new house have no internet?

Two separate problems stack on each other, and this is the version of this question that matters most around here, because there is a lot of new construction going up.

First, your house might not exist yet as far as the map knows. The FCC builds its location list from parcel data, tax records and imagery. Their own documentation admits it. The source data "may not be up to date with current, real-world conditions (such as the recent construction of a new subdivision)." That list updates roughly every six months. Stack that on the reporting lag and a house finished in spring can be missing from the published map well into the following year.

Second, somebody has to pay to run the line. In a new subdivision, the distribution plant, the conduit and the drops to each house are a construction project with a budget, a permit and a schedule. Who pays for it is a private agreement between the developer and the provider. It isn't set by any law I could find, so the only way to know is to ask who signed what.

And houses close one at a time while plant gets built for the whole phase. So your house can be finished, inspected and closed months before the phase it sits in has service.

The question that cuts through all of it, and you ask this at the builder's sales office: is any home in this subdivision currently receiving service? Then ask which provider has a signed agreement for your phase, whether conduit is in the ground, and what the projected activation date is relative to your closing date. Get it in writing. A sales office answer that won't go in writing is its own answer.

Why does an address a mile away have more options?

Because service obligations aren't written against every address in the county. They're written against defined footprints.

Under Illinois law, a video and broadband provider's service area gets defined by exchanges, census blocks or units of local government, and the build-out requirement is a percentage: access to 35 percent of households within three years, 50 percent within five. Look at the shape of that. It's a percentage of a defined area. A provider can satisfy the requirement completely and never build the low-density edge of it, and the low-density edge is exactly where unincorporated Will County sits.

That's the whole explanation for why a subdivision inside village limits has three options and a farmhouse a mile out has one. Nothing about the terrain changed. What changed is the math of who counts toward the obligation.

It's the same boundary problem that shows up everywhere out here. A mailing address is not a municipality, and the line that decides your fire district and your school district also shapes what shows up on that map.

One more thing on the rural edge: AT&T has notified Illinois customers that traditional copper landline service is being discontinued on or after March 15, 2027. That's the same physical copper that carries DSL. The announcement addresses phone service and doesn't specifically say DSL is ending, so nobody should tell you it's being shut off. But copper's on a retirement path, and that's a real reason not to buy a house whose only wired option is DSL.

What's actually different between fiber, cable and 5G home internet?

Four things, and only one of them's the number providers advertise.

Upload speed is the one that matters most and gets mentioned least. Fiber's typically symmetrical, so your upload roughly matches your download. Cable's heavily lopsided toward download. If two people in your house are on video calls while a kid uploads to a cloud drive, you have an upload problem, and cable is where upload is thinnest.

Latency is the delay rather than the speed, and it isn't the number the ads are selling you. The FCC's own description names the use case that matters: high latency "can disrupt real-time services like telehealth visits." Fiber's lowest. Geostationary satellite's worst by a wide margin. Low-earth-orbit satellite's much better than the old satellite, but it's still above fiber.

Data caps. More common on fixed wireless and satellite than on fiber.

Congestion and weather. Cable runs on a shared neighborhood node, so evenings slow down. Fixed wireless and 5G home internet are capacity-limited at the tower. That's why service can be genuinely unavailable at your address while your neighbor's got it. Satellite's affected by weather and by trees.

There's a clean way to compare plans without trusting anybody's marketing. Since 2024, providers have been required to post a standardized broadband consumer label at the point of sale, online and in stores, and the FCC requires the actual label rather than a link to one. It lists typical upload, typical latency, the data allowance and the real price after the intro rate. Pull the label for the plan you'd actually buy. That's the comparison.

How do you check cell service at a house?

Stand in the house and use your phone, because no map will tell you.

This is the single most important thing in this article, and it comes straight from the FCC: the National Broadband Map "does not include information on the availability of mobile wireless broadband service while indoors." Mobile coverage maps show where you should connect outdoors or in a moving vehicle. That's how they're built and that's how they're validated, by driving a car down your street.

Every carrier map has the same limitation. So a buyer standing in the driveway with four bars has learned nothing about the basement office.

Modern construction makes it worse. Low-E windows, foil-faced sheathing, brick and a finished basement all cut signal. That's why a newer house can be worse than an older one on the same street.

So at the showing: the kitchen, the basement, the room that's going to be the office, and the primary bedroom. Every carrier your household actually uses, which may mean bringing a second phone or asking your agent. And place an actual call. Don't read the bars. Then step outside and compare, because that gap is what you'll be asking wifi calling to cover.

Here's the part that should settle it. The FCC does run a challenge process for mobile coverage, but a valid challenge test has to be run outdoors or in a vehicle. There's no regulatory remedy for a weak signal in your own living room. That's not a complaint you can file. It's a decision you make before you buy.

Does wifi calling fix bad cell service?

Mostly yes, with three conditions, and the first one is circular in a way that matters.

It needs working home internet with enough upload. Wifi calling fixes weak cell only if you've already fixed the internet question. At an address with neither, it fixes nothing.

It needs a registered 911 address, and this one is a genuine safety issue people miss. Providers have to get your physical location before activating service, and they have to give you a way to update it. If you move and don't update it, your 911 call can route to your old town's dispatch. Out here a move can cross from Cook into Will County and change which center answers. Update it the day you move in.

And it fails when the power does. The FCC says it plainly: voice over internet "may not work during a power outage or when the internet connection fails or becomes overloaded." A house with no cell signal, running voice over wifi, in a power cut, has no way to call anyone. If you're on call for work, that isn't a small thing.

What to do before you write the offer

In order, cheapest first.

Run the exact address through broadbandmap.fcc.gov. Confirm it appears in capitals. Turn off the 25 Mbps filter. Write down every provider, the technology, and both speed numbers.
Treat that as a call list. Available means a ten-business-day claim, not a line at your curb.
Call each provider with the address and ask four things: is this specific address serviceable today or does it need construction, what's the install lead time, are there construction or line-extension charges beyond normal activation, and what technology actually reaches this address. Ask for it by email. Those emails are also your evidence if you ever need to challenge the map.
Pull the consumer label for the plan you'd buy. Check upload, latency and the data allowance.
Test cell at the showing, in the rooms you'll use, on every carrier, with a real call.
Ask the seller, or the builder's sales office, in writing. Who's your provider, what do you actually pay, have you had outages or trouble getting installed, does anyone here use wifi calling and why.

If you're looking at a rural-edge address, one more: federal broadband funding may eventually reach it, and Illinois publishes a map of funded build areas. That's good news for year three and completely irrelevant to your move-in date. Don't let a funding map substitute for step three.

Does the seller have to tell you?

No, and this is worth knowing before you assume the disclosure will cover it.

The Illinois Residential Real Property Disclosure Report is set by statute and has twenty-four numbered items. Flooding, foundation, roof, walls, electrical, plumbing, well, drinking water, heating, fireplace, septic, radon, asbestos, lead, mine subsidence, termites, fuel tanks, boundary disputes, code violations. It's a long and specific list. Not one of them mentions internet, broadband, cable, telephone or cell service.

And the ones that touch utilities ask about material defects in physical systems. That's equipment condition, not service availability. The form asks about things being broken, not about things being absent. A house that never had internet has no defective internet system to disclose.

So an Illinois seller has no duty to tell you that an address can't get broadband or that your phone won't work in the basement.

There's no standard contingency for it either. If it matters enough to you, that's a conversation with your attorney during attorney review about a custom rider. Have that conversation early rather than as an afterthought.

Which brings it back around: this is a due diligence problem, not a disclosure problem. The law won't hand you the answer. You have to go get it, and you have to go get it before the offer, because after closing the standard form gives you nothing.

The Bottom Line

Nobody in the transaction is checking this for you. And the form that's supposed to tell you what's wrong with a house doesn't ask the question.

The federal map is the right place to start and the wrong place to stop, because "available" there means a company says it could hook you up in ten business days. Call the providers with the actual address. Get the answer in an email.

For cell, forget every map. They're all outdoor maps by design, and there's no complaint you can file about a dead basement. Stand in the room you'll be working in and make a call.

And if you're buying new construction, ask the sales office one question before anything else: is any house in this subdivision getting service right now. Everything else follows from the answer.

It's twenty minutes. The alternative is finding out in week two, with the boxes still packed, that the room you picked for your office doesn't work for the thing you do for a living.

Frequently Asked Questions

Is the FCC broadband map accurate?

It's the best public starting point and it systematically overstates availability. Providers self-report, the standard lets them count addresses they could serve rather than addresses they do serve, and the published data is six to eleven months behind. Use it to build your list of providers to call, not as your answer.

What can I do if the map is wrong about my address?

File an availability challenge at broadbandmap.fcc.gov. The provider has to either concede or rebut it, and the FCC adjudicates what doesn't get resolved. Screenshots and emails from the provider are your evidence. Understand the timing though: there's no published deadline for resolution, so this fixes the record rather than your closing date.

My new house isn't on the map at all. What does that mean?

Usually that the FCC's location data hasn't caught up with the construction, which is common and expected. You can file a location challenge to add the address. It doesn't tell you anything about whether service is available, so it doesn't replace calling the providers.

Is 5G home internet a real replacement for cable or fiber?

For some households, genuinely yes. It depends on your distance from the tower, line of sight, and how loaded that tower is, which is why availability is decided address by address and can be no at your house and yes next door. Check the upload speed and the data policy on the consumer label before you count on it for work.

My HOA says no satellite dishes. Can they do that?

Generally not, for a dish one meter or smaller. A federal rule protects your right to install a small satellite dish or a fixed wireless antenna and bars HOA rules that prevent or delay it, and the association has the burden of proving any restriction valid. It covers areas of exclusive use, not shared common areas.

Should I make my offer contingent on internet service?

There's no standard contingency for it in Illinois, but your attorney can write one during the attorney review period. Whether it's worth the negotiating capital depends on how much your work depends on it. For most buyers, verifying before the offer is faster and costs nothing.

Does the county or village have anything to do with what's available?

Indirectly, and more than people think. Service areas and build-out obligations are written against defined municipal and census boundaries, so being inside village limits versus unincorporated genuinely changes your options. It's the same boundary line that decides your fire district and your school district.

If the map was wrong about your address, or a provider told you something different than what's here, send it to me. Real answers from real addresses out here are worth more than anything the map says.

If you work from home or you're on call, tell me before we start looking and we'll check availability on every address before you tour it instead of after you love the house. Set up a time and we'll build that into the search from day one.

Brian Wittman is a licensed real estate broker (Real Broker LLC), mortgage loan originator (NMLS #2646598, NEXA Mortgage, LLC, Equal Housing Lender), and life insurance producer (Levinson & Associates). This article is for educational purposes only and is not financial, lending, tax, or legal advice, an offer, or a commitment to lend; all loans are subject to credit approval. Information is accurate as of the publication date; for current details and full disclosures, visit https://bluejeanbroker.com/disclosures.