Clay Waterfall Enrichment: 95%+ Hit Rate Guide

Most B2B teams rely on a single data provider and accept 40–60% email coverage as "good enough." That means 4–6 out of every 10 prospects you researched, scored, and qualified never get an email. Waterfall enrichment fixes this by chaining multiple providers in sequence — and with the right setup in Clay, you can hit 95%+ coverage with validated, deliverable data.

This guide walks through the exact setup, provider ordering, formulas, validation steps, and cost math to build a production-grade waterfall in Clay.

What is Waterfall Enrichment?

Waterfall enrichment is a sequential lookup strategy. Instead of sending every record to one provider and accepting the misses, you cascade through multiple providers:

1. Send the record to Provider A (your highest-accuracy source)
2. If Provider A returns no result, send the record to Provider B
3. If Provider B misses, try Provider C
4. Continue until you find the data or exhaust all providers

The key insight: every B2B data provider has blind spots. Apollo might have strong coverage for US-based SaaS companies but miss European manufacturing firms. Hunter excels at pattern-based emails but can't verify catch-all domains. By combining providers, you fill each other's gaps.

Why Single-Provider Coverage Falls Short

Here are realistic coverage numbers when you use a single provider for work email lookup:

No single provider breaks 70% coverage consistently. But when you waterfall LeadMagic → Apollo → Hunter, you combine those coverage pools. The overlap between providers is typically only 30–40%, meaning each fallback provider catches a meaningful chunk of the records the previous one missed.

The math works out: if Provider A covers 65% and Provider B covers 55% of the remaining 35%, your combined coverage is 65% + (35% × 55%) = 84.25%. Add a third provider and you're pushing past 90%.

Why LeadMagic Should Be Your Primary Provider

Provider order matters — a lot. Your primary provider runs on every single record, so it needs to be:

1. The most accurate — bad data at the top of the waterfall poisons everything downstream
2. Real-time verified — stale databases return emails that bounce
3. Cost-effective at scale — it processes the most records

LeadMagic checks all three:

• 97% accuracy rate — the highest in Clay's integration marketplace. Every email returned by the Email Finder is verified in real-time against the mail server, not pulled from a static database.
• Real-time SMTP verification — LeadMagic connects to the recipient's mail server at lookup time. If the mailbox doesn't exist or rejects connections, you don't get charged and the email isn't returned.
• Catch-all domain handling — When a domain accepts all emails (making verification impossible), LeadMagic flags it. You can then route those to the Catch-All Validation endpoint for deeper analysis instead of blindly trusting a pattern guess.
• Credit-based plans from $59.99/mo — No annual contracts or per-seat fees. You pay per successful lookup, which keeps waterfall costs predictable. Credits roll over on Essential+ plans.

Placing LeadMagic first means 60–70% of your records get resolved with high-confidence data on the first pass. Fallback providers only process the remaining 30–40%, reducing both cost and risk.

Prerequisites

Before you start building, make sure you have:

• A Clay account (Starter plan or above — free plans have limited enrichment credits)
• A LeadMagic account with an API key (sign up at leadmagic.io)
• A contact list with at minimum: First Name, Last Name, and Company Domain (LinkedIn URL also works for some providers)
• Optionally, accounts with 1–2 fallback providers (Apollo, Hunter, Dropcontact, etc.)

Step 1: Setting Up Your Clay Table

Start by creating a new table and importing your prospect data.

Import Sources

Clay supports several import methods:

• CSV upload — Export from your CRM, a Sales Navigator search, or any spreadsheet
• CRM integration — Pull directly from HubSpot, Salesforce, or Pipedrive
• Clay's Find People — Use Clay's built-in prospecting to build lists from scratch
• API/Webhook — Push records in programmatically from your own tooling

Required Columns

Your table needs these columns at minimum for an email waterfall:

Domain cleanup tip: If you only have company names (not domains), add a Clay enrichment column to find the company website first. Clay's "Find Company Domain" enrichment or a simple Google search column can handle this. Don't pass full URLs like https://www.stripe.com/about — strip it down to stripe.com.

Clean Your Data Before Enriching

Run a quick check before you start spending credits:

1. Remove duplicates — Sort by Last Name + Domain and deduplicate
2. Filter out personal emails — If any existing email column has gmail.com, yahoo.com, etc., flag those rows (they won't benefit from a B2B email waterfall)
3. Verify domains aren't empty — Rows without a domain will fail every lookup and waste credits. Filter them out or enrich domains first.

Step 2: Adding LeadMagic Email Finder as Primary

This is the first and most important enrichment column in your waterfall.

1. Click "+ Add Column" in your Clay table
2. Select "Enrich Data" from the column type options
3. Search for "LeadMagic" in the enrichment provider list
4. Select "Email Finder"

Field Mapping

Map your Clay columns to the LeadMagic API fields:

5. Click "Run Enrichment" to process all rows

LeadMagic will return several fields per row:

• email — The verified work email address
• confidence — Confidence score (high, medium, low)
• verification_status — Whether the email was verified against the mail server

For most rows (60–70%), you'll get a verified email on this first pass. The remaining rows show empty results — that's where your fallback providers come in.

Step 3: Adding Fallback Providers with Conditional Logic

The key to a cost-efficient waterfall is conditional execution. You only want fallback providers to run on rows where LeadMagic returned no result.

Adding Your First Fallback

1. Click "+ Add Column" → "Enrich Data"
2. Select your second provider (e.g., Apollo, Hunter, or Dropcontact)
3. Before mapping fields, click "Add Condition"
4. Set the condition: "LeadMagic Email Finder → email" is empty
5. Map the same input fields (First Name, Last Name, Domain)
6. Run enrichment

This condition ensures the fallback only runs (and charges you) when LeadMagic didn't return an email. Without it, you'd pay for duplicate lookups on records you already have data for.

Adding a Second Fallback (Optional)

If two providers still leave gaps, add a third column:

1. Add another enrichment column with your third provider
2. Set condition: "LeadMagic Email Finder → email" is empty AND "Fallback 1 → email" is empty
3. Map fields and run

Diminishing returns warning: each additional provider adds cost and complexity but returns fewer incremental records. For most use cases, 2–3 providers total is the sweet spot. Going beyond 3 rarely adds more than 3–5% coverage.

Step 4: Consolidating Results with Formulas

After your waterfall runs, you have email data scattered across multiple columns. Create a single consolidated column.

1. Click "+ Add Column" → "Formula"
2. Name it "Final Email"
3. Use this formula:

IF({LeadMagic Email Finder → email} != "", {LeadMagic Email Finder → email},
  IF({Fallback Provider 1 → email} != "", {Fallback Provider 1 → email},
    IF({Fallback Provider 2 → email} != "", {Fallback Provider 2 → email}, "")))

This formula checks each provider column in order and returns the first non-empty email. The priority order matches your waterfall — LeadMagic results take precedence because they're the most accurate.

Adding a Source Tracking Column

It's useful to know which provider found each email. Add another formula column called "Email Source":

IF({LeadMagic Email Finder → email} != "", "LeadMagic",
  IF({Fallback Provider 1 → email} != "", "Apollo",
    IF({Fallback Provider 2 → email} != "", "Hunter", "Not Found")))

This lets you analyze provider performance later — which provider returned the most results, which had the best deliverability, and where you should allocate budget.

Step 5: Validating All Emails with LeadMagic Email Validation

This is the step most teams skip, and it's the one that matters most. Even if a provider "found" an email, that doesn't mean it's deliverable. People change jobs, companies reorganize, and databases go stale.

LeadMagic Email Validation checks every email against the live mail server to confirm it actually accepts messages.

Setup

1. Click "+ Add Column" → "Enrich Data"
2. Search for "LeadMagic" → Select "Email Validation"
3. Map the input: point it to your "Final Email" consolidated column
4. Add a condition: "Final Email" is not empty (no point validating blank rows)
5. Run the validation

Understanding Validation Results

LeadMagic returns a status for each email:

Filtering Your Final List

Create a filtered view or formula column to keep only validated emails:

IF({Email Validation → status} = "valid", {Final Email}, "")

For risky emails (often catch-all domains), you have two options:

1. Conservative: Exclude them entirely
2. Aggressive: Include them but route through LeadMagic Catch-All Validation for a deeper check

The conservative approach keeps your bounce rate under 1%. The aggressive approach pushes coverage higher but may result in 2–3% bounces on the catch-all segment.

Step 6: Building a Phone Number Waterfall

Email alone isn't enough for modern outbound. Adding direct phone numbers alongside your email waterfall dramatically increases connection rates. The setup follows the same waterfall logic.

Adding LeadMagic Mobile Finder

1. Click "+ Add Column" → "Enrich Data"
2. Search for "LeadMagic" → Select "Mobile Finder"
3. Map the input fields:
   • LinkedIn URL or email — LeadMagic uses either to find direct mobile numbers
4. Run enrichment

The LeadMagic Mobile Finder returns direct dial numbers — not switchboard or office lines. Expect 40–60% coverage depending on your prospect segment (senior executives tend to have higher mobile coverage than junior roles).

Combining Email + Phone Waterfalls

Your final table should have these consolidated columns:

Create the "Has Phone" column with:

IF({Mobile Finder → phone} != "", TRUE, FALSE)

This lets you create segments like "has valid email AND phone" for your highest-priority outreach sequences.

Provider Order Optimization

The order you stack providers in your waterfall directly impacts cost and quality. Here's the reasoning behind the optimal order.

Recommended Email Waterfall Order

Why Not Put the Cheapest Provider First?

It's tempting to put the cheapest provider first to save money. Don't. Here's why:

1. Accuracy compounds downstream — If your first provider returns a wrong email at 80% accuracy, your waterfall stops and you have a bad email in your final list. LeadMagic's 97% accuracy means fewer false positives that slip through.
2. Validation catches bad data, but it costs extra — Every wrong email from an inaccurate provider still passes through your validation step. You pay the validation credit for an email that gets flagged as invalid.
3. Net cost is what matters — A cheap provider with 80% accuracy that returns results for 55% of records gives you usable data for 44% (55% × 80%). LeadMagic at 97% accuracy and 65% coverage gives you usable data for 63% (65% × 97%). The per-usable-email cost often favors the accurate provider.

Detailed Cost Breakdown

Let's do real math for two scenarios. Prices reflect typical credit-based rates.

Scenario A: 1,000 Contacts

Result: ~880 verified emails (88% coverage) + ~500 mobile numbers (50% coverage)

Cost per verified email: $0.065 — well below the $0.10–$0.30 range for manual research or premium databases.

Scenario B: 10,000 Contacts

Result: ~8,800 verified emails + ~5,000 mobile numbers

At 10k contacts, you're paying $0.098 per fully enriched contact (email + phone + validation). Compare that to buying a static list at $0.50–$1.00 per contact with no accuracy guarantee.

Reducing Costs Further

• Skip phone enrichment on low-priority segments — Mobile Finder is the largest single cost item. Run it only on prospects that match your ICP.
• Use conditional logic aggressively — Don't just condition fallback providers. Condition on job title, company size, or lead score to only enrich high-value records.
• Cache results — If you re-import contacts that were already enriched, use Clay's deduplication or a lookup formula to avoid paying twice for the same person.

Advanced Tips

Scheduled Enrichment for Growing Lists

If you're pushing new prospects into Clay continuously (from Sales Navigator, HubSpot, or webhooks), set up Clay's auto-enrichment:

1. Enable "Run on new rows" for each enrichment column
2. New records automatically flow through the waterfall as they arrive
3. Set up a Clay webhook or Zapier trigger to push validated results back to your CRM

This turns your Clay table into a real-time enrichment engine rather than a one-time batch process.

Conditional Enrichment by Segment

Not every prospect deserves the full waterfall. Use Clay conditions to create tiered enrichment:

• Tier 1 (ICP match): Full waterfall + mobile finder + validation
• Tier 2 (secondary targets): LeadMagic only + validation (skip fallbacks)
• Tier 3 (long tail): Skip enrichment, use for marketing only

This can cut costs by 40–50% while maintaining full coverage on the accounts that matter most.

Using Clay AI Columns for Data Cleanup

Clay's AI column feature can help with pre-waterfall data prep:

• Extract domains from URLs — If you have company LinkedIn URLs but not domains, use an AI column with the prompt: "Extract the root domain from this company website URL"
• Standardize names — Fix capitalization, remove titles (Dr., Mr.), and split full names into first/last
• Classify catch-all results — After enrichment, use AI to help decide whether to include risky/catch-all emails based on the company profile

HTTP API Column for Custom Logic

For teams with specific needs, Clay's HTTP API column lets you call the LeadMagic API directly:

POST https://api.leadmagic.io/email-finder
Headers: X-API-Key: your_api_key
Body: {"first_name": "{First Name}", "last_name": "{Last Name}", "domain": "{Domain}"}

This gives you access to the full API response (including metadata fields) that the native integration might not surface.

Common Mistakes to Avoid

1. Skipping Email Validation

The biggest mistake. Even the best providers return emails that go stale. A 2–3% bounce rate across 10,000 emails means 200–300 bounces — enough to damage your sender reputation. Always run LeadMagic Email Validation as the final step.

2. Using Too Many Fallback Providers

More providers ≠ better results. After 3 providers, you're typically adding less than 3% incremental coverage while increasing cost and complexity. If your first 2–3 providers cover 90%+, the remaining 10% likely can't be found by anyone.

3. Not Setting Conditions on Fallback Columns

Without conditions, every row runs through every provider. You pay for duplicate lookups on contacts that already have verified emails. Always set the "is empty" condition on fallback columns.

4. Enriching Bad Input Data

Garbage in, garbage out. If your "Domain" column has values like "N/A", "unknown", or full URLs, every provider will fail and you'll waste credits. Clean your input data first.

5. Ignoring Catch-All Domains

About 20–30% of business domains are configured as "catch-all" — they accept email to any address at the domain. Standard verification can't confirm if a specific mailbox exists on these domains. Treat catch-all results carefully or route them through specialized catch-all validation.

6. Running Phone Enrichment on Every Record

Mobile numbers are valuable but the enrichment is more expensive. Run the Mobile Finder selectively — on prospects you'll actually call. For email-only sequences, skip it.

Expected Results

With the waterfall configuration described in this guide, here's what to expect:

These numbers assume a B2B prospect list with mostly US/European companies. Coverage may be lower for regions with less data provider coverage (Asia-Pacific, Latin America) and higher for well-covered segments like US tech companies.

Tracking Performance Over Time

Keep your "Email Source" column to monitor provider performance. Each month, check:

1. Hit rate by provider — Is your primary provider's coverage shifting?
2. Validation pass rate by source — Which provider's emails have the highest valid rate?
3. Bounce rate by source — After sending, which provider's emails actually bounced?

If a fallback provider consistently delivers higher valid rates than your primary on certain segments, consider reordering the waterfall for those segments.

Putting It All Together

Here's the complete column structure for your Clay table, in order:

1. First Name — Input
2. Last Name — Input
3. Company Domain — Input
4. LinkedIn URL — Input (optional)
5. LeadMagic Email Finder — Primary enrichment
6. Apollo Email — Fallback 1 (conditioned on #5 empty)
7. Hunter Email — Fallback 2 (conditioned on #5 and #6 empty)
8. Final Email — Formula consolidating #5, #6, #7
9. Email Source — Formula tracking which provider found the email
10. Email Validation — LeadMagic Email Validation on #8
11. Validated Email — Formula filtering to valid-only from #8 + #10
12. Mobile Number — LeadMagic Mobile Finder
13. Has Phone — Formula (TRUE/FALSE)

That's 13 columns from input to fully enriched, validated, multi-channel contact data. The whole waterfall runs in minutes for 1,000 records and handles 10,000+ without issues.

Next Steps

• Set up your first waterfall — Start with LeadMagic as your primary and one fallback. You can always add more providers later.
• Explore the full LeadMagic + Clay integration — See our Clay integration page for all available enrichment types.
• Go deeper on individual tools — Check out the Email Finder, Email Validation, and Mobile Finder product pages for API docs and advanced options.
• Learn about waterfall strategy — Our waterfall enrichment solution page covers the methodology beyond Clay-specific setup.

The bottom line: a well-configured waterfall turns a 60% coverage list into a 95% coverage list. The setup takes 30 minutes. The ROI compounds on every outbound campaign you run.