Quick answer
Waterfall enrichment asks several data providers for the same work email or phone number, one after another, and stops when one returns a verified result. You find more contacts than any single database has, and with most tools you only pay when something is found. Clay runs them across 150+ providers (free plan, paid from $185 a month). Apollo (Basic plan and up) and Lusha (Pro and up) have one built in. Dedicated tools such as FullEnrich (25+ sources, from $29 a month) and BetterContact (20+ providers, from $15 a month) run the chain for you. On their entry paid plans, a found work email costs roughly 3 to 25 cents and a mobile 20 cents to about $1. It's worth it for large lists across several countries, niche markets and mobiles. It's overkill for a few hundred contacts in one country that your main database already covers. Prices checked on 15 October 2026.
How waterfall enrichment works
I'm a GTM consultant, and the contact data I help teams set up feeds cold email and LinkedIn sequences. The waterfall is usually where most of the data budget goes, so here's how it works and bills, taken from each vendor's own pages. No tool in this article pays me, and there are no affiliate links.
- Start with what you know: a name and company domain, or a LinkedIn profile URL.
- Provider 1 looks for a work email (or a mobile, in a phone waterfall).
- If it finds one, a verifier checks it. Verified: the chain stops and you pay provider 1.
- If nothing came back or it failed verification, the same person goes to provider 2, then 3, and so on.
- After the last provider, the person lands in a not-found pile.
Two settings decide the bill. First, the stop rule: stop at the first result or keep going until a verified one. Apollo lets an admin choose and warns that waiting for a verified result costs more, because each provider that returns an unverified email still charges. Second, whether misses cost money. Clay, Lusha, FullEnrich and BetterContact all say a lookup that finds nothing costs nothing.
Why one database misses people
Every provider builds its data its own way. Apollo, for example, says it combines a contributor network of its users, bounces and replies from its own sending tools, web crawling and third-party records. Another provider leans on different sources, so each has gaps the others don't.
The vendors selling waterfalls put numbers on it. BetterContact says a single source finds only 30 to 60% of emails or mobiles on average. Clay's waterfall guide says OpenAI roughly doubled its inbound enrichment coverage, from about 40% to 80%, after moving from one provider to Clay's waterfall. Both are sales claims from companies that sell waterfalls. Take the direction from them, then measure what a second source adds on your own list.
Tools that run waterfalls (checked 15 October 2026)
| Tool | Sources | What you pay for | Credits per email / mobile | Entry price |
|---|---|---|---|---|
| Clay | 150+ providers; the email waterfall runs across 100+ | Only the lookup that returns data. Your own API keys skip Data Credits | Set per provider, Data Credits from $0.05 each | Free plan (no phones); Launch $185 a month, $167 billed yearly |
| Apollo | Apollo's data, then the providers your admin adds | Each source that returns data, verified or not. A validator charges per check | Typically 1 to 4 per email, 8 to 25 per phone (Apollo's estimate) | Basic, $65 a seat a month or $49 billed yearly |
| Lusha | Lusha's data, then the extra providers an admin turns on | Matches only | Own data 1 / 5. Extra providers 2 / 8 | Pro, $69.90 a month for 600 credits |
| FullEnrich | 25+ sources | Data that's found and passes verification | 1 / 10 (personal email 3) | $29 a month for 500 credits, 50 free credits to try |
| BetterContact | 20+ providers | Valid data only, emails verified by Bouncer | 1 / 10 | $15 a month for 200 credits, $49 for 1,000, 50 free credits |
They fall into three groups:
- Inside the database you already pay for: Apollo and Lusha. One admin setting and it runs for the whole team. Lusha says its waterfall completes contacts it already holds rather than finding new people. Apollo shows a credit estimate before each run and lets admins cap credits per user.
- A workflow tool: Clay. The most control: a different order per segment, your own provider keys, a verification step and AI research columns in the same table. Someone has to build and maintain it. I compare the two approaches in Clay vs Apollo.
- A dedicated waterfall tool: FullEnrich and BetterContact. Upload a CSV or call the API and the vendor runs the chain. BetterContact names RocketReach, Apollo, ContactOut, Datagma, People Data Labs, Prospeo and Hunter among its sources. FullEnrich includes unlimited users on every plan.
What a found contact costs
My math from each pricing page: the monthly plan price divided by its credits, times the credits each found result uses.
| Tool and plan, monthly billing | Per found work email | Per found mobile |
|---|---|---|
| Apollo Basic ($65, 2,500 credits) | About 3 to 10 cents | About 21 to 65 cents |
| Lusha Pro ($69.90, 600 credits) | 12 cents from Lusha, 23 cents from an extra provider | 58 cents from Lusha, 93 cents from an extra provider |
| FullEnrich ($55, 1,000 credits) | 5.5 cents | 55 cents |
| BetterContact ($49, 1,000 credits) | 4.9 cents | 49 cents |
| Clay | Data Credits from $0.05 each, times the credit price of whichever provider finds the match | |
Apollo's ranges are its own "typical" figures, and it says an email can go over 20 credits and a phone over 45 in some cases. Most of these tools cut the price per credit at higher volumes.
Here's why the model saves money. Say your main database finds 600 of your 1,000 emails. You send only the 400 misses down the waterfall. At BetterContact's Pro rate, every one it finds costs 4.9 cents. If it finds 200, you've paid $9.80 for them. You never paid twice for the 600 easy ones.
The rule that saves the most credits. Run the waterfall only on people you'll actually contact, after you've filtered the list. And run the phone waterfall only for people you'll call: on the tools above, a mobile uses 4 to 10 times the credits of an email.
How to set one up without wasting credits
- Test before you choose the order. Run 100 to 200 of your real contacts through each candidate. Put the source that finds the most on your market, at the lowest cost per found email, first.
- Verify at every step. An email that fails verification counts as a miss and goes to the next provider. If you add a separate validator in Apollo, it charges every time it checks, so one contact checked across three sources pays three times.
- Pick the stop rule on purpose. First result is cheaper. First verified result is safer for your domains.
- Keep email and phone waterfalls separate, with phones only for the people you'll call.
- Don't pay twice for the same person. Apollo won't call the same source again for a contact within 30 days if it returned usable data. In Clay, keep results in the table and don't re-run rows.
- Log which provider found each contact and re-test every few months. Coverage shifts.
For the verifier itself, see my email verification tools comparison.
When it's worth it, and when it isn't
Worth it if
- Your list runs into the thousands, across several countries.
- A test sample shows your main database misses a real share of the people you want.
- You sell into a niche market or need mobiles for calling.
Skip it if
- You have a few hundred accounts in one country and your database already finds most of them. A five-step chain costs more in setup time than it returns.
- Nobody will own the setup or watch the credit spend.
- You'd skip verification anyway. Extra unverified emails only add bounces.
One more check for European sellers: every provider in the chain is one more company whose data sources and GDPR terms you should be comfortable with.
Where the waterfall fits in outbound
Map out the companies first, then the people, then run the waterfall. In that order you only pay to find people you'll actually email. After that comes verification, then the sequence. I go through the full chain in how to build a data enrichment pipeline.
The not-found pile isn't a dead end. This is how I set it up for clients: email and LinkedIn in one sequence, so a person the waterfall can't find still gets the LinkedIn steps instead of dropping out. If you're still choosing the database that sits at the top of the chain, see Lusha vs Apollo.
Key takeaways
- A waterfall asks one provider after another for the same email or phone and stops at the first verified result.
- Clay, Lusha, FullEnrich and BetterContact don't charge for misses. Apollo charges each source that returns data, verified or not.
- On entry paid plans a found email costs roughly 3 to 25 cents and a mobile 20 cents to about $1 (checked 15 October 2026).
- Verify at every step, run phones only for people you'll call and enrich after you filter the list.
- Worth it for big, mixed-country or niche lists. Skip it for a small single-country list your database already covers.
FAQ
What is waterfall enrichment?
It's a way of finding contact data by asking several providers in a set order. If the first one doesn't return a verified email or phone number, the next one tries, until one finds it or the list of providers runs out.
How much does waterfall enrichment cost?
On the entry paid plans I checked on 15 October 2026, a found work email cost roughly 3 to 25 cents and a found mobile 20 cents to about $1. Most tools don't charge when nothing is found. Apollo charges each source that returns data.
Does Apollo have waterfall enrichment?
Yes, on Basic, Professional and Organization. Apollo checks its own data first and then the providers your admin adds. It charges credits for each source that returns data. Apollo puts a typical email run at 1 to 4 credits and a phone run at 8 to 25.
What is the best waterfall enrichment tool?
It depends on your setup. If you already pay for Apollo or Lusha, turn on theirs first. Clay gives the most control if someone will build the tables. FullEnrich and BetterContact suit teams that want to upload a list and pay only for found, verified data.
Is waterfall enrichment worth it?
For lists in the thousands, across several countries or in a niche market, usually yes, because one database misses part of the list. For a few hundred contacts in one country that your main tool already covers, the extra setup rarely pays back.