How long CCTV actually keeps footage, and why you must act in days, not weeks.

Last reviewed: 18 July 2026

Retention is maths, not policy

Ask a shop owner how long their cameras keep footage and you'll often hear a confident number that turns out to be wrong. That's because retention isn't a setting anyone chose. It's the output of an equation: hard drive size, divided by the number of cameras, times the quality and frame rate each one records at.

A recorder writes video onto a disk until the disk is full, then goes back to the start and records over the oldest footage. More cameras or higher quality means the disk fills faster and the window shrinks. Typical small-business and home systems hold somewhere between several days and a few weeks; a system someone upgraded with extra cameras but not extra storage can hold much less than its owner believes. Motion-triggered recording stretches the window; a busy scene shrinks it again.

Two systems that look identical on the wall can have wildly different windows. The only way to know the real number is to check the recorder, and the only safe assumption until then is that the window is short.

Overwrite is continuous, not monthly

The second misunderstanding is the idea that footage gets "cleaned out" periodically, so a quiet few weeks are safe. Overwrite doesn't work in batches. The recorder is deleting the oldest hour of footage more or less every hour, around the clock, weekends included. Each day you wait, one more day of history falls off the back of the recording, permanently.

That gives every incident a hard, invisible deadline: the day the footage of your incident becomes the oldest footage on the disk. You won't be told when that day is. On a system with a ten-day window, an incident from last Tuesday is already most of the way to the edge.

The preservation steps, in order

Ask in writing, immediately. The same day you learn footage might exist, send the owner or operator a short written request: date, time range, camera or area, and a clear ask, please preserve and export footage of this period, and please don't wait. Email is fine. The writing matters twice over: it's harder to ignore than a phone call, and it establishes exactly when the operator knew the footage was wanted, which becomes relevant if it later "disappears".

Get the native export, not a phone video of the screen. The helpful version of an export is the file produced by the recorder itself, copied to a USB stick, along with the player software many recorders bundle with it. A phone filmed at a monitor loses resolution, timestamps, and credibility, and it captures only what someone chose to play for you. If the export arrives in a strange format that nothing will open, that is normal and it's still the right file to have, keep the original untouched, and don't let anyone "helpfully" convert it.

Record the recorder's clock error. While the export is being made, have someone photograph the recorder's on-screen time next to a phone showing actual time. DVR clocks drift, sometimes by minutes, occasionally by hours or the wrong timezone entirely, and every timestamp in the export inherits that error. A known offset, documented on the day, keeps the timeline honest; an unknown offset lets the other side dismiss it. If the clock is plainly wrong, you can still rebuild a reliable timeline from the footage.

Widen the time range and the camera list. Export more than the incident: the hour before and after, and the cameras covering approaches and exits, not just the spot itself. Vehicles arriving, people leaving, lights coming on, context footage is where timelines are actually built, and it's covered by the same few minutes of asking. Once you have hours of it, you can triage the footage by movement instead of watching all of it.

Why an exported copy beats a promise

"They said they'd keep it" is the sentence that precedes most lost footage. The operator means well on the day. Then the recorder keeps overwriting because nobody actually changed anything, or the system fails, gets unplugged, or is replaced, or the business changes hands, or the person who promised goes on leave. A promise leaves the footage on the one disk in the world that is actively deleting it.

An exported copy in your possession ends all of that. Once the file is on a USB stick and backed up somewhere second, the recorder's window no longer matters. Everything before export is urgent; everything after can proceed at legal speed.

If the window has already closed

Ask anyway, but ask wider. The recorder's window may be gone while a copy still exists somewhere: a clip someone exported at the time, a snippet shared to a phone, a monitoring company's separately stored alerts, a neighbouring premises whose system has a longer window and a useful angle. Council and transport cameras run on their own retention schedules and their own request processes, and those clocks are ticking too. The original deadline being missed makes the remaining copies more valuable, not less.

The short version

CCTV retention is disk size divided by cameras and quality, typically days to a few weeks, and the recorder overwrites the oldest footage continuously, so every day of delay permanently deletes a day of history. Ask for preservation in writing the same day, insist on the recorder's native export rather than a phone video of a screen, photograph the recorder's clock against real time, and export wide. A copy in your hand beats any promise, because the promise leaves the footage on a disk that is busy deleting it.

General guidance only, for footage that may matter legally, get advice on evidence handling in your state before anyone modifies the recorder.

Where this comes from

Background reading on the technology described above, so you can check any of it yourself rather than take our word for it:

• Wikipedia: Closed-circuit television, an overview of how CCTV systems are put together and how footage is recorded.
• Wikipedia: Digital video recorder, what a DVR is, how it writes to disk, and how recording capacity works.