# What is waterfall enrichment, and how does it work?

> Waterfall enrichment asks contact data sources in turn until one returns a checked result. How the order is set, what it costs and where it falls short.

By Wade, Duckrow's research desk (a house pen name). Published 2026-10-21, updated 2026-10-21.

Waterfall enrichment is a way to find a contact detail, like a work email or a mobile number, by asking several data sources in turn. If the first source finds nothing usable, the next one tries, and so on. It stops at the first checked result, so you get wider coverage than one source gives and pay for one find.

## Why ask more than one data source?
Each contact data source builds its records its own way, so each one knows different people. One may be strong on large tech companies, another on small firms, another on a region. Asking several in turn finds people that any single source misses.

The catch is cost and quality. Every extra source you ask can cost money, and a source that guesses can return an address that bounces. A good waterfall controls both.

## How is the order of sources decided?
The order decides your cost. A useful measure is the cost of one verified result: what a source charges per lookup divided by how often it finds a verified result.

For example, a source that charges 2 cents and finds a verified email 40% of the time costs 5 cents per verified email. A source that charges 3 cents and finds one 75% of the time costs 4 cents. The second one should go first, even though each lookup costs more.

Hit rates change by list and over time, so the order works best when it is measured and updated as results come in.

## What makes a waterfall result trustworthy?
A check on every result before it counts. A source can return a guess. An email checker asks the mail server whether the address exists, without sending a message. If the answer is anything but valid, the waterfall moves on to the next source.

| Pricing model | What you pay for | What to watch |
| --- | --- | --- |
| Per lookup | Every attempt, found or not | Long waterfalls get expensive on hard lists |
| Per result | Every address returned | Unchecked guesses that bounce |
| Per verified result | Only addresses that pass a check | What the provider counts as verified |

## How does Duckrow's waterfall work?
Every find in Duckrow (work email, mobile and LinkedIn profile, in columns, Find leads, Find the right people, the Assistant and the MCP connector) goes through one engine.

- For work emails, Duckrow's own finder goes first: addresses printed on the business's site, then common patterns, each one checked.
- Then each connected data source, ordered by its cost per verified result over the last 30 days. One lookup in ten puts another source first, so the rates stay honest.
- An email counts only when the check says valid. A domain that accepts every address can't be confirmed, so the likeliest address is kept beside the miss, marked unconfirmed and not charged.
- You pay only on a hit: 6 credits for a work email, 50 for a mobile, 2 for a LinkedIn profile. A miss costs nothing.
- Cells and exports never name the source.

An "Only if Jev says yes" check can sit in front of a find. Jev answers a question about the row first, for 1 credit, and a No skips the paid find.

## What are the limits of waterfall enrichment?
A waterfall can only find people some source knows. Small local businesses, new companies and people who keep a low profile can be missing from every source.

In Duckrow, which sources answer depends on the ones connected and funded when you run the find. When a source is out of credits or down, it is skipped, so hit rates move from week to week. You still pay only for hits.

## Questions
### Is waterfall enrichment the same as an email finder?
An email finder is one source. A waterfall asks several finders in turn and stops at the first checked result.

### Do I pay for every source the waterfall asks?
That depends on the tool. In Duckrow you pay only when a checked result is found: 6 credits for a work email, 50 for a mobile.

### Can I see which provider found an email in Duckrow?
No. Cells, exports and usage history show the result only.

### What inputs does a waterfall need?
A first or last name with a company domain or name, or a LinkedIn profile link. The more you give, the more sources can try.

## Sources
- IETF RFC 5321: Simple Mail Transfer Protocol: https://www.rfc-editor.org/rfc/rfc5321
- Duckrow: Lead tables: https://duckrow.ai/product/lead-tables
- Duckrow: Pricing: https://duckrow.ai/pricing

Page: https://duckrow.ai/blog/what-is-waterfall-enrichment