RadNet is a nationwide network of radiation monitors run by the EPA that measures radiation levels in the air, precipitation, and drinking water

RadNet stands for Radiation Network, a system of monitoring stations across the United States that continuously measure environmental radiation. The EPA (Environmental Protection Agency) operates these stations and makes the data public. You can see real-time readings from stations near you on the EPA's website without logging in or paying anything.

The monitors track three types of radiation exposure: airborne radiation (measured in the air), precipitation (in rain and snow), and drinking water. Each station reports its findings regularly, and the EPA publishes all results online. This is different from medical imaging like MRI — RadNet measures what's in your environment, not what's inside your body.

RadNet became more visible to the public after the 2011 Fukushima nuclear accident in Japan, when people wanted to know whether radiation from that event had reached the United States. The network has existed since the 1970s, but public interest in checking local readings has grown since then.

Key Takeaways

  • RadNet stations measure radiation in air, rain, and drinking water across all 50 states, and the EPA publishes all readings online for free.
  • You can search for the station nearest you and see current and historical radiation levels without creating an account.
  • RadNet data is used to detect unusual radiation spikes, track natural background radiation, and monitor for contamination from nuclear accidents or incidents.
  • Radiation levels in most areas remain stable and within normal ranges; RadNet alerts the public only when readings exceed established safety thresholds.

How to find RadNet data for your location

The EPA hosts an interactive map on its RadNet website where you can enter your zip code or city name and see which monitoring stations are closest to you. Each station shows its most recent measurements and allows you to view historical data going back years. The map updates regularly — most stations report new readings daily or weekly, depending on the type of measurement.

When you click on a station, you see three separate data streams: air samples (measured in picocuries per cubic meter), precipitation samples (measured in picocuries per liter), and drinking water samples (also in picocuries per liter). Not every station measures all three — some locations have only air monitors, while others have the full set. The EPA's map tells you which measurements each station provides.

You can read raw data files from the EPA's RadNet database if you want to analyze trends yourself or create your own charts. These files are free and require no registration. The EPA also publishes an annual RadNet report summarizing national radiation trends and any unusual findings from that year.

What the numbers mean and what counts as normal

Radiation is measured in units called picocuries (pCi). One picocurie is one trillionth of a curie, a unit of radioactivity. The numbers you see on RadNet are small — typically in the range of 0.001 to 0.01 picocuries per cubic meter for air, depending on your location and time of year. These levels are considered normal background radiation, which comes from natural sources like uranium in soil, radon gas, and cosmic radiation from space.

Background radiation varies by geography. Areas with granite bedrock or higher elevation tend to show slightly higher readings because of natural uranium and radon. Coastal areas and areas downwind of certain geological formations may also show variation. The EPA does not set a single "safe" number for all locations — instead, it tracks what is normal for each region and watches for spikes above that baseline.

If a RadNet station detects radiation levels significantly higher than its historical average, the EPA investigates the cause. This might be a false reading (equipment malfunction), a local source (medical facility, industrial process), or something more serious. The EPA publishes alerts and press releases when unusual readings occur, so you would hear about it through news outlets and the agency's website before you would notice it on the map yourself.

Why the EPA runs RadNet and what it is used for

RadNet serves several purposes. First, it provides a baseline of natural background radiation across the country, which helps scientists understand how radiation levels change with geography and season. Second, it acts as an early warning system — if a nuclear power plant accident, weapons test, or other incident releases radiation, RadNet stations would detect it before it reached dangerous levels in populated areas. Third, it gives the public transparency; anyone can check whether radiation near them is within normal ranges.

The network is also part of the United States' commitment to international radiation monitoring agreements. Other countries run similar networks, and the data is shared to track global radiation patterns. This is especially important after events like nuclear accidents, where radiation can travel across borders.

RadNet does not replace personal dosimeters or medical radiation monitoring. If you work in a field where you are exposed to radiation (nuclear power, medical imaging, research), your employer provides personal monitoring devices. RadNet tells you about environmental radiation in your community, not your individual exposure.

Understanding RadNet alerts and what to do if readings spike

RadNet stations are designed to detect spikes quickly. If a reading is unusually high, the EPA's system flags it for review. Most flagged readings turn out to be equipment errors or temporary anomalies. When the EPA confirms that a spike is real and significant, it issues a public statement explaining the source and whether any action is needed.

In the event of a confirmed spike from a serious source (such as a nuclear accident), the EPA would issue guidance through multiple channels: its website, press releases, state health departments, and emergency alert systems. You would not need to check RadNet yourself — the information would reach you through news and official channels. The EPA also coordinates with the Nuclear Regulatory Commission (NRC), which oversees nuclear power plants and would provide additional guidance if a plant-related incident occurred.

For routine elevated readings that do not indicate a public health threat, the EPA publishes explanations on its website. For example, if a medical facility nearby uses radioactive materials, that might cause a small local spike that is not a concern for the general public.

RadNet data and privacy

RadNet data is public and anonymized — it measures radiation in the environment, not in people. The EPA does not collect personal information when you view RadNet data online. You can check your local station as often as you want without creating an account, logging in, or providing your name or location.

The data itself is owned by the EPA and is available under the Freedom of Information Act (FOIA). Researchers, journalists, and members of the public regularly request and publish RadNet data for analysis. Some independent websites republish RadNet data in different formats or with additional analysis, but the underlying measurements all come from the EPA's official network.

Frequently Asked Questions

Is the radiation measured by RadNet dangerous?

No. RadNet measures background radiation, which is present everywhere and is not harmful at normal levels. Humans are exposed to background radiation constantly from natural sources. RadNet alerts the public only if levels spike significantly above the normal range for that location, which is rare.

Can I use RadNet data to check if my home is safe?

RadNet tells you about radiation in the air and water in your general area, but it does not measure radiation inside your home. If you are concerned about radon gas in your home specifically, you would need a separate radon test kit, which you can purchase from hardware stores. RadNet is a community-level monitoring tool, not a home inspection tool.

How often does RadNet update its readings?

Most RadNet stations report new air measurements daily or weekly. Precipitation and drinking water samples are collected and analyzed less frequently — sometimes monthly or quarterly — because these measurements take longer to process. The EPA's website shows the date of the most recent reading for each station and measurement type.

What should I do if I see a high reading on RadNet?

First, check whether the reading is actually unusual by comparing it to the station's historical data — the EPA's website shows both. If it is genuinely high and you are concerned, contact your state health department or the EPA's regional office. Do not assume a single high reading means danger; the EPA investigates spikes and publishes explanations for significant ones.

Does RadNet measure radiation from nuclear power plants?

RadNet stations near nuclear power plants do measure radiation in the environment, but they are not the primary monitoring system for those facilities. The Nuclear Regulatory Commission (NRC) requires power plants to operate their own monitoring networks. RadNet provides an independent, public check on environmental radiation levels nationwide.