What is waterfall enrichment?
Waterfall enrichment is looking up a missing detail, such as a work email or phone number, by asking several data suppliers in turn and stopping at the first one that returns a usable answer. It finds more contacts than any single supplier, at the cost of more moving parts.
How a waterfall runs
- Take a person with a name and a company.
- Ask supplier A for their work email. If it returns a verified address, stop.
- If not, ask supplier B. Then C. Then D.
- Verify whatever comes back before you count it as found.
The order matters because you pay per step. A waterfall is a trade between coverage and cost.
A worked example
Say you need emails for 1,000 people. Prices and hit rates below are illustrative, not quotes from any vendor.
| Step | Supplier cost per hit | Hit rate on what is left | Found | Running total found |
|---|---|---|---|---|
| A | 2 cents | 55% | 550 | 550 |
| B | 3 cents | 30% of 450 | 135 | 685 |
| C | 6 cents | 20% of 315 | 63 | 748 |
If only hits are billed, the cost is 550 x 2 + 135 x 3 + 63 x 6 = 1,883 cents, about $18.83 for 748 emails, or roughly 2.5 cents each. Stopping after step B gives 685 emails for $15.05. Step C added 63 emails for $3.78, which is 6 cents each. Whether that is worth it depends on what one reply is worth to you.
Now change one rule: if every step bills per request, hit or miss, step C alone charges for 315 lookups. Billing policy can matter more than supplier price, which is why our piece on why Clay credits disappear spends so long on it.
Common mistakes
- Counting found as good. A waterfall that returns an unverified guess at step C has not found anything yet. Run email verification on every result.
- Too many steps. Each extra supplier finds fewer contacts at a higher price per contact. Measure the marginal cost of the last step.
- Ignoring billing for misses. Policies differ. Clay's pricing page says an enrichment that returns no result is not charged. Apollo's waterfall charges per source that returns data, including unverified emails found along the way.
Related terms
A waterfall is one technique within data enrichment. Its output feeds your bounce rate: a looser waterfall finds more addresses and usually bounces more of them.
How Sluice runs it
Sluice's email and phone lookups ask your chosen supplier first, then the cheapest usable runners-up, and stop at the first that has the answer. A miss is not billed, and every email is verified independently before it is charged. Lookups are priced at supplier cost plus a markup that falls with the plan, or no markup on Agency with your own data key (pricing).
Questions people ask
- Why use a waterfall instead of one data provider?
- Every provider has gaps: some are strong in the US, others in Europe or in particular industries. Asking a second and third supplier fills gaps the first one has, so more of your list ends up with a contact.
- Do you pay for every supplier in a waterfall?
- It depends on the tool. Some charge only when a step returns something usable. Others charge per supplier that returns data, including unverified emails found along the way. Check the billing page before you run a large list.
- What order should a waterfall run in?
- Usually cheapest acceptable quality first, then more expensive suppliers for what is left. If one supplier is clearly best for your market, put it first even if it costs more.
Sources
Try it on your own market
Sluice quotes the worst-case price before anything runs and charges only for lookups that found something, so finding out costs close to nothing.
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