How does waterfall enrichment work in Clay?
Waterfall enrichment asks data providers one at a time. If the first provider finds nothing, Clay asks the next one. It stops when it finds a value that passes. Each lead gets several chances to be filled, and you do not pay every provider for data you already have.
As of October 2026, Clay's waterfall page puts it this way: it lets you "search sequentially across multiple tools until you find a valid match." In plain words, the order of your list decides who gets asked first.
- Step 1: Clay sends the lead to the first provider on your list.
- Step 2: If no email comes back, Clay tries the next provider.
- Step 3: If an email comes back, a check runs on it.
- Step 4: If the email fails the check, the next provider gets a turn.
- Step 5: The waterfall stops at the first email that passes.
This is why order matters. Put the provider that covers your market best at the top. Put cheaper or narrower sources lower down, so they only fill what is left.
Getting the order right takes a few test runs. If you would rather not tune it yourself, a Clay workflow expert can build and test it with you.
How do you set up a Clay lead enrichment workflow?
Set it up in 6 stages: choose the fields you need, clean the input, fill company data, fill people data, check the results, then send clean rows on. Each stage feeds the next one. If you skip a stage, the gaps show up later as bounces, repeats or leads with no owner.
| Stage | What you do | Why it matters |
|---|---|---|
| 1. Pick fields | Split must-have fields (name, title, company, email) from nice-to-have fields (phone, LinkedIn URL) | You only pay to fill what your team will use |
| 2. Clean input | Fix company names and remove repeats before any lookup | Repeats waste lookups and make 2 records for 1 person |
| 3. Fill company data | Find the domain, size and industry first | Person lookups hit more often with a clean domain |
| 4. Fill people data | Run the email waterfall, then the phone waterfall if you need it | Each gap gets several chances |
| 5. Check | Run an email check and flag risky results | A found email can still bounce |
| 6. Send on | Pass only checked rows to your CRM or sending tool | Bad rows never reach a rep |
Make each paid step run only when the field is still empty. Clay's own company data lesson says to "set up conditional runs so enrichments only run when needed." That one rule stops you paying twice for the same field.
Stage 6 is where most repeats slip in. The Clay and HubSpot sync guide covers match keys and field rules for that step.
Which data sources should feed the waterfall?
No single source fills every field. Test 2 or 3 providers on a sample of your own leads, then rank them by how many checked emails each one finds. Put the best one first. Coverage changes a lot by country, industry and job level, so a test on your own list beats any ranking.
The gap between tools is wide. In June 2026, Anymail Finder ran a test of 14 email finders on 5,000 business contacts across the US, UK, France and Germany. Coverage ran from 41.3% for the lowest tool to 87.1% for the highest.
Anymail Finder makes one of the tools it tested, so treat its own rank with care. The spread is still the point.
- People data providers: emails, phone numbers and job titles
- Company data providers: domain, size, industry and tech used
- Public sources: company websites, news and public records
- Your own data: CRM history, form fills and past replies
Public sources matter more than most teams think. In a national waste client's target market, about 9 in 10 qualified sites did not appear in the standard commercial database. The engine found them from independent public sources.
Every extra provider adds cost per lookup. Check what Clay costs to run before you add a fourth source.
How do you verify enriched contacts before they reach your CRM?
Run an email check inside the waterfall, before any lead moves on. The check tells you if a mailbox exists. Mark each email as safe, risky or bad, and only pass the safe ones forward. Hold catch-all emails apart, since a catch-all domain accepts mail for any name, real or not.
As of October 2026, Clay's waterfall lesson says it uses ZeroBounce to check emails by default, and you can swap in another tool. It also says catch-all emails come back as valid unless you turn on the setting that only marks safe emails as valid. Turn that setting on for cold outreach.
- Safe: the mailbox exists. Pass it on.
- Catch-all: the domain takes all mail, so the mailbox is not confirmed. Hold it, or send to it in small test batches.
- Bad: the mailbox does not exist. Drop it and try the next provider.
- Unknown: the check could not tell. Log it as unknown and do not count it as filled.
Log the reason for every drop. If one provider keeps failing checks, move it down the list. Once leads pass, the Clay to Smartlead setup covers how to send without hurting your domain.
How do you measure fill rate, and what target should you set?
Fill rate is the share of rows that hold a checked value for a field. Measure it field by field, after the check, not before. Set your target from a pilot on your own leads. Run 500 to 1,000 records, note the fill rate for each must-have field, then tune the order and run again.
A filled field is not the same as a good field. ZeroBounce's 2026 Email List Decay Report found that only 62% of the emails sent to it for checks in 2025 were valid. More than 9% were catch-all. So a 100% email fill rate before checks can hide a lot of bad data.
Track these 4 numbers in a log table:
- Fill rate per field: rows with a checked value, divided by all rows
- Check pass rate: emails marked safe, divided by emails found
- Unknown rate: rows the check could not settle
- Cost per filled row: total spend, divided by rows that pass
We work to one rule in our own builds: every fact we deliver carries its source. If we cannot verify it, we say so, and we do not fill gaps with guesses. An unknown is shown as unknown, never rounded up to zero. That rule keeps your fill rate real, because a guessed email counts as a gap, not a hit.
If your fill rate stalls after 2 rounds of tuning, talk to our team.
How often should you re-enrich, and what does Australian privacy law expect?
Re-check your data on a set timer, every 3 to 6 months for active lists. People change jobs and firms open and close, so good data goes stale. In Australia, the Privacy Act also asks you to take reasonable steps to keep personal data accurate, up to date and complete.
Business churn in Australia is high. The Australian Bureau of Statistics counted 460,461 new businesses and 375,331 that closed in 2025-26. ZeroBounce's 2026 report also found that at least 23% of an email list goes bad each year.
The law points the same way. As of October 2026, Australian Privacy Principle 10, published by the Office of the Australian Information Commissioner, says an entity "must take reasonable steps to ensure the personal information it collects is accurate, up to date and complete."
- Re-check only active rows. Leads you will not contact this quarter can wait.
- Re-check the fields that move. Job title and email change most, while company domain rarely does.
- Keep the source and date. Log where each value came from and when, so you can answer a privacy request.
- Sync with care. Write fresh values to empty or Clay-owned fields only, so a rep's own edits stay in place.
Clay Workflows
Book a 30-minute workflow audit. We review your provider order, email checks and fill rate, then show you where the gaps are.
FAQs
What is lead enrichment?
Lead enrichment adds missing details to a lead record, such as job title, work email, phone number and company size. It turns a name and a company into a record a rep can act on. Good enrichment also checks the data, so the details are right, not just present.
Is Clay a data enrichment tool?
Yes. Clay links to many data providers and lets you ask them in order, which is called a waterfall. It also runs checks, scores and AI steps in the same table. That makes it a place to build an enrichment workflow, not a single database.
What are the best waterfall enrichment tools?
There is no single best tool for every market. Coverage changes by country, industry and job level. Test 2 or 3 providers on a sample of your own leads. Rank them by how many checked emails each one finds, not by how many emails it returns.
How many data sources should you start with?
Start with the default provider order in Clay, then test. As of October 2026, Clay's email waterfall comes with 6 providers by default. Add a new source only when it fills a gap the others miss in your pilot.
Is email verification legit?
Yes. An email check asks the mail server if a mailbox exists, without sending a message. It cannot confirm every address, because catch-all domains accept mail for any name. Treat catch-all results as risky, not safe.
Can you run Clay enrichment without a CRM?
Yes. You can run the full workflow in Clay and export the checked rows as a file. A CRM link just makes it easier to route leads to owners, block repeats and refresh records on a timer.