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BigQuery, safer by default from September 2025

A snippet of an email from Google, showing the change in BigQuery project quota defaults

On September 1st 2025, Google will make BigQuery a lot safer by default, changing the default quotas for projects under the default on-demand pricing model. Instead of unlimited financial damage, the default for new projects will be around $1000 per day. Existing projects will be updated to a custom limit based on prior 30-day usage. No changes to existing limits.

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I received an email entitled "[Action Advised] Review and set appropriate daily usage limit for BigQuery projects before Sep 1, 2025." yesterday. The content is a big step forward for making BigQuery safer by default. Unfortunately, Google's copyrighted the content so I can't share it in full here, and the quota documentation doesn't cover the full content, but I can summarize the key points.

New projects

As of September 1st, 2025, new projects using the default on-demand BigQuery pricing model will have a daily usage limit of 200TiB. The current model has no default limit, potentially leading to unlimited financial exposure - as I've written about in $1,370 Gone in Sixty Seconds, explaining how a single query could run up a bill over $1,300 in less than a minute, and in The BigQuery Safety Net, explaining how the quota system can mitigate these risks.

200TiB is still a lot, and at the $5/TiB current pricing, it's $1000 per day. Most SMEs won't be affected, but an unexpected spike could still be painful. I see no indication that any smart adjustments will be made automatically based on usage patterns, so I'll still be setting my own values for these quotas anyway.

Existing projects

If a project already has a quota value other than unlimited set for QueryUsagePerDay or QueryUsagePerUserPerDay, then no changes will be made. Otherwise, Google will set a quota based on usage in the last 30 days.

Auditing

The changes will be visible in audit logs when they occur.

Summary

There are a whole bunch of blog posts out there that are going to need updating!

Here are the updated BigQuery quota-related docs. BigQuery's defaults are about to get a lot safer, but could still hurt to the tune of $1000/day. I'll still be setting my own much lower values when I set up projects that use BigQuery.


Feedback

If you want to get in touch with me about the content in this post, you can find me on LinkedIn or raise an issue/start a discussion in the GitHub repo. I'll be happy to credit you for any corrections or additions!

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