21 email list hygiene statistics that matter: 2026 edition
Nearly a quarter of every email list goes bad each year - yet most senders rarely clean. These 21 sourced statistics show how fast lists decay, what dead addresses cost you, and the hygiene levers that keep you landing in Primary.
Every email list is quietly rotting. People change jobs, abandon inboxes, mistype their address at signup, or hand you a throwaway domain to grab a lead magnet. None of that shows up in your open rate - it shows up months later as rising bounces, spam-trap hits, and a sender reputation that slowly slides toward the spam folder. List hygiene is the discipline of catching that decay before mailbox providers do.
The uncomfortable part is how few senders keep up with it. Lists shed nearly a quarter of their reachable addresses every year, but the majority of senders clean infrequently, skip verification at signup, and never set a policy for cutting off dead weight. That gap between how fast lists decay and how rarely they are cleaned is where deliverability quietly bleeds out.
Here are 21 sourced email list hygiene statistics for 2026 - covering list decay rates, how often senders actually clean, spam traps and invalid addresses, the measurable impact of verification, re-engagement and sunset policies, and the cost of poor hygiene - with what each one means for your program.
Key takeaways
- At least 23% of an email list goes bad every year - decay peaked at 28% in 2024 before improving in 2025.
- Marketing databases degrade about 22.5% every year, or roughly 2.1% a month.
- Nearly 40% of senders rarely or never conduct list hygiene.
- Invalid addresses were 20.19% of emails checked in 2022 - the single biggest data-quality problem.
- Email verification identifies invalid and risky addresses with 99.6% accuracy.
- Only 24% of senders use a sunset policy for unengaged subscribers.
How fast lists decay
1. At least 23% of an email list goes bad every year
ZeroBounce's 2025 analysis found that at least 23% of an email list goes bad every year as addresses are abandoned, changed, or deactivated. Nearly a quarter of the people you can reach today will be unreachable within twelve months - which is why hygiene is a continuous process, not a one-time cleanup.
2. List decay peaked at 28% in 2024 before improving to 23% in 2025
The decay rate is not static. ZeroBounce tracked it peaking at 28% in 2024 before improving to 23% in 2025. Even in a better year, though, more than one address in five rots off your list - so the trend line offers no excuse to slow down on cleaning.
3. Marketing databases degrade about 22.5% every year
HubSpot, citing MarketingSherpa, found that marketing databases degrade by about 22.5% every year - roughly 2.1% per month for B2B - as contacts change jobs and abandon addresses. It is a remarkably consistent figure across sources: expect to lose about a fifth to a quarter of your list annually to natural decay alone.
4. Only 57.21% of emails submitted in 2022 were valid
Looking at an older benchmark year, ZeroBounce reported that only 57.21% of emails submitted in 2022 were valid, with about 22.71% decaying over that year. The gap between what people submit and what is actually mailable is enormous - which is why validation at the point of capture matters as much as periodic cleaning.
How often senders actually clean
5. Nearly 40% of senders rarely or never conduct list hygiene
Mailgun found that nearly 40% of senders rarely or never conduct list hygiene. Set against a list that decays more than 20% a year, infrequent cleaning all but guarantees rising bounces - it is one of the most common and most avoidable deliverability wounds.
6. Only about 27% of senders clean their lists monthly or more often
Mailgun's breakdown of cleaning frequency shows 27% cleaning monthly or more, 16% quarterly, 18% once or twice a year, 27% rarely, and 12% never. Because lists lose roughly 2% of addresses every month, only the monthly-plus cohort is really keeping pace with decay; everyone else is falling behind between cleans.
7. Only 13% of senders use inbox placement tests
Hygiene is not just about removing bad addresses - it is about knowing whether your mail lands. Mailgun found that only 13% of senders use inbox placement tests. The vast majority are flying blind on the exact outcome hygiene is meant to protect, unable to see placement slipping until engagement drops.
8. 9.4% of senders admit buying lists or scraping contacts
Poor hygiene often starts at acquisition. Mailgun found 9.4% of senders admit to buying lists or scraping contacts - rising to 14-15% among senders mailing 100,000+ contacts. Purchased and scraped addresses are dense with spam traps and invalids, so this practice manufactures the exact problems clean-up is trying to solve.
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Spam traps and invalid addresses
9. Spam traps make up only about 0.01% of checked addresses
Spam traps are rare but disproportionately dangerous. ZeroBounce's 2025 data shows they make up only about 0.01% of checked addresses. A single trap hit can trigger blocklisting, so even a vanishingly small share of your list can inflict outsized reputation damage - the reason verification screens for them specifically.
10. In 2025, 62% of validated addresses were valid and 9% were catch-all
ZeroBounce found that in 2025, 62% of validated addresses were valid and 9% were catch-all. The remainder - invalid, risky, disposable, and unknown addresses - is the portion actively working against your deliverability, and the whole point of running validation is to separate the reliable 62% from the rest.
11. Invalid addresses were 20.19% of emails checked in 2022
In its 2022 benchmark, ZeroBounce found that invalid addresses made up 20.19% of emails checked - the single biggest data-quality problem it measured. Roughly one address in five was undeliverable before a campaign even started, which is exactly the kind of dead weight that drives bounces past the reputation-damaging threshold.
12. ZeroBounce found 10M+ typos and 5M+ disposable addresses in a single year
The scale of bad data is easy to underestimate. In 2022, ZeroBounce identified more than 10 million typo addresses and over 5 million disposable addresses. Typos and throwaway domains slip through most signup forms unnoticed - and each one is a guaranteed bounce or a subscriber who was never really reachable.
13. A bounce rate above 2% starts to damage reputation and inbox placement
ZeroBounce notes that a bounce rate above 2% starts to damage sender reputation and inbox placement. That 2% ceiling is the practical reason all the decay and invalid-address numbers matter: they are the inputs that push your bounce rate past the line where mailbox providers begin to filter you.
What verification changes
14. Email verification identifies invalid and risky addresses with 99.6% accuracy
ZeroBounce reports that email verification identifies invalid and risky addresses with 99.6% accuracy. That precision is what makes verification a direct deliverability lever rather than guesswork - you can suppress almost every address that would otherwise bounce, before it ever costs you reputation.
15. Only 30% of senders validate emails at signup, and just 13% run bulk validation
Despite that accuracy, adoption is thin. Mailgun found only 30% of senders validate emails at signup, and just 13% run bulk validation. Most senders let invalid addresses onto the list at capture and never sweep them out later - leaving the highest-accuracy hygiene tool available largely unused.
16. Reducing bounces is a top deliverability challenge for 28.4% of senders
The consequence of skipping verification shows up in the challenges senders report. Mailgun found that reducing bounces is a top deliverability challenge for 28.4% of senders. Bounces are largely a solved problem - validation handles them - yet more than a quarter of senders still struggle, because they are not using the tools that would fix it.
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Re-engagement and inactive subscribers
17. Only 24% of senders use a sunset policy for unengaged subscribers
A sunset policy automatically stops mailing subscribers who have gone quiet, protecting reputation from engagement-based negative signals. Yet Mailgun found only 24% of senders use a sunset policy for unengaged subscribers. Three-quarters keep mailing dead weight indefinitely - one of the clearest gaps between best practice and common practice in list hygiene.
18. Sunset-policy adoption scales with volume: 50.3% of 1M+ senders versus 17% of the smallest
The senders who feel reputation pain most are the ones who act. Mailgun found sunset-policy adoption climbs with volume, from 50.3% of senders mailing 1M+ a month down to about 17% of sub-50K senders. High-volume programs learn that suppressing inactives is essential; smaller senders often discover it only after a placement problem.
19. 57.4% of senders monitor opens and clicks, but fewer than 15% see engagement as a key reputation driver
There is a disconnect between what senders track and what they believe matters. Mailgun found 57.4% of senders monitor opens and clicks, but fewer than 15% see engagement as a key reputation driver. Mailbox providers weigh engagement heavily, so underrating it leads senders to keep mailing inactives - the precise behavior a sunset policy exists to prevent.
The cost of poor hygiene
20. Gmail and Yahoo require a spam-complaint rate below 0.1% - and never 0.3%
Poor hygiene ends in complaints, and the ceilings are unforgiving. Google's guidelines require bulk senders to keep the spam-complaint rate below 0.1% and never let it reach 0.3%, with Yahoo matching the rule. That 0.3% red line is just three complaints per 1,000 messages - a threshold a stale, poorly cleaned list can cross quickly.
21. 30% of companies earn $36-$50 back per $1, and 5% earn more than $50 - returns that hinge on inbox placement
The upside of getting hygiene right is money. Litmus found 30% of companies earn $36-$50 back per $1 spent, and 5% earn more than $50 - returns that hinge entirely on inbox placement. Those elite economics are reached only by senders whose mail actually lands, which is precisely what disciplined list hygiene protects.
What this means: the list hygiene playbook
Treat decay as a constant, not an event. At least 23% of a list goes bad every year, and databases degrade about 22.5% annually - roughly 2% a month. A one-time cleanup does nothing against a list that is losing addresses continuously. Build hygiene into a recurring schedule so you are always cleaning faster than the list decays.
Validate at the door and in bulk. Verification identifies invalid and risky addresses with 99.6% accuracy, yet only 30% of senders validate at signup and just 13% run bulk validation. Invalid addresses can be a fifth of an unverified list. Catch them at capture and sweep the existing list periodically - it is the single most accurate hygiene lever you have.
Set a sunset policy and act on engagement. Only 24% of senders sunset unengaged subscribers, and fewer than 15% treat engagement as a key reputation driver - even though mailbox providers weigh it heavily. Stop mailing subscribers who have gone quiet after a re-engagement attempt. Suppressing dead weight protects the reputation your active subscribers depend on.
Keep bounces under 2% and complaints under 0.1%. A bounce rate above 2% starts to damage reputation, and Gmail's enforced complaint ceiling is 0.3% - never to be reached, ideally under 0.1%. Both thresholds are downstream of hygiene: clean lists bounce less and complain less. Watch these numbers as the early-warning system for a list that needs cleaning.
Guard the ROI that hygiene protects. The top senders earn $36-$50 or more back per $1, but only because their mail lands. Every dead address, spam trap, and unengaged subscriber chips away at the placement that makes those returns possible. Before you scale, test your real inbox placement so you catch hygiene problems while they are still cheap to fix.