Waterfall Enrichment in Clay: The Complete Guide

Learn how to set up waterfall enrichment in Clay to maximize data coverage while minimizing costs. Step-by-step setup with provider recommendations.

Waterfall enrichment is Clay’s most powerful feature. Instead of relying on a single data provider, you chain multiple sources together—each one filling gaps the previous sources missed.

The result? Coverage rates of 80-90% instead of the 40-60% you’d get from any single provider.

This guide shows you exactly how to set it up.

What Is Waterfall Enrichment?

A waterfall works like this:

Input: john@acme.com
           │
           ▼
    ┌─────────────┐
    │  Provider 1 │ → Found email? → Use it ✓
    │   (Apollo)  │
    └─────────────┘
           │ No result
           ▼
    ┌─────────────┐
    │  Provider 2 │ → Found email? → Use it ✓
    │   (Hunter)  │
    └─────────────┘
           │ No result
           ▼
    ┌─────────────┐
    │  Provider 3 │ → Found email? → Use it ✓
    │ (Dropcontact)│
    └─────────────┘
           │ No result
           ▼
    ┌─────────────┐
    │  Provider 4 │ → Found email? → Use it ✓
    │  (FindyMail)│
    └─────────────┘
           │ No result
           ▼
      No email found

Each provider only runs if the previous one failed. You only pay for successful lookups.

Why Waterfall Enrichment Works

No Single Provider Has Everything

Every data provider has gaps:

  • Apollo is strong in tech/startup contacts, weaker in traditional industries
  • ZoomInfo excels at enterprise, less coverage for SMB
  • Hunter finds publicly listed emails, misses those not on websites
  • Dropcontact is excellent for European data

By combining them, you cover each provider’s blind spots.

Real Coverage Numbers

Here’s what we typically see with email enrichment:

ApproachCoverage RateCost Efficiency
Single provider40-55%Baseline
2-provider waterfall60-70%Good
3-provider waterfall75-85%Excellent
4+ provider waterfall80-90%Diminishing returns

The sweet spot is usually 3-4 providers. Beyond that, you get minimal additional coverage.

Setting Up Your First Waterfall

Let’s build an email waterfall step by step.

Step 1: Create Your Table

Start with a Clay table containing:

  • First name
  • Last name
  • Company name or domain

You can import from CSV, your CRM, or use Clay’s prospecting tools.

Step 2: Add Your Primary Enrichment

Add your first email enrichment column:

  1. Click + Add Column
  2. Select Enrichment
  3. Choose your primary provider (e.g., Apollo)
  4. Map the input fields (name, company)
  5. Select the output field (work email)

Step 3: Add Fallback Enrichments

Now add your second provider:

  1. Click + Add Column
  2. Select Enrichment
  3. Choose your fallback provider (e.g., Hunter)
  4. Important: Set a condition—only run if the first column is empty

In Clay, you set this condition in the enrichment settings:

Only run when: {Apollo Email} is empty

Repeat for your third and fourth providers.

Step 4: Create the Final Email Column

Add a formula column that consolidates all results:

COALESCE(
  {Apollo Email},
  {Hunter Email},
  {Dropcontact Email},
  {FindyMail Email}
)

This returns the first non-empty value—your best email.

Step 5: Add Verification

Always verify emails before using them:

  1. Add a verification enrichment (NeverBounce, ZeroBounce, MillionVerifier)
  2. Only run on rows where you found an email
  3. Filter out invalid results

Based on testing across thousands of records, here are optimized waterfall sequences:

Email Finding Waterfall

1. Apollo (best overall coverage, good accuracy)
      ↓
2. Hunter (strong for public emails)
      ↓
3. Dropcontact (excellent EU coverage, GDPR compliant)
      ↓
4. FindyMail (good catch-all detection)
      ↓
5. Verify with NeverBounce or ZeroBounce

Why this order?

  • Apollo has the broadest database and is cost-effective
  • Hunter catches publicly listed emails Apollo misses
  • Dropcontact excels where others fail (especially in Europe)
  • FindyMail as a final fallback with good catch-all handling

Phone Number Waterfall

1. Apollo (includes direct dials)
      ↓
2. Cognism (strong EU phone data)
      ↓
3. Lusha (good direct dial coverage)
      ↓
4. RocketReach (fallback)

Company Data Waterfall

1. Clearbit (cleanest data, best coverage for tech)
      ↓
2. Apollo (broader industry coverage)
      ↓
3. PeopleDataLabs (backup with good global coverage)

Advanced Waterfall Strategies

Strategy 1: Conditional Provider Selection

Not all providers are equal for all segments. Use conditions:

IF {Industry} = "Technology" THEN
  Use Apollo first
ELSE IF {Country} = "Germany" THEN
  Use Dropcontact first
ELSE
  Use Hunter first

In Clay, you’d create separate enrichment columns with appropriate conditions.

Strategy 2: Cost Optimization

Order providers by cost (cheapest first):

1. Hunter ($0.01/lookup) - Try free/cheap first
      ↓
2. Apollo ($0.02/lookup) - Good value
      ↓
3. ZoomInfo ($0.10/lookup) - Premium, use sparingly

This maximizes coverage while minimizing spend.

Strategy 3: Quality Tiers

Create quality tiers in your output:

Tier 1: Verified email from primary source
Tier 2: Verified email from fallback source
Tier 3: Unverified email (use with caution)
Tier 4: No email found

Use different outreach strategies for each tier.

Strategy 4: Parallel Then Sequential

For maximum speed on large datasets:

Run in parallel:
  - Apollo
  - Hunter
  - Clearbit

Then sequentially (only if all parallel failed):
  - Dropcontact
  - FindyMail

This balances speed with coverage.

Common Waterfall Mistakes

Mistake 1: Not Verifying Emails

Enrichment providers return emails—they don’t guarantee deliverability. Always add a verification step.

Bad approach:

Apollo → Hunter → Send emails

Good approach:

Apollo → Hunter → NeverBounce → Send verified emails

Mistake 2: Too Many Providers

More isn’t always better. After 4-5 providers, you hit diminishing returns and increase complexity.

Coverage by provider count:

  • 1 provider: 45%
  • 2 providers: 65%
  • 3 providers: 78%
  • 4 providers: 84%
  • 5 providers: 86%
  • 6 providers: 87%

The jump from 4 to 6 providers barely moves the needle.

Mistake 3: Wrong Provider Order

Provider order matters. Put your highest-coverage, most-accurate provider first.

Bad order (based on alphabetical):

Clearbit → Dropcontact → Hunter → ZoomInfo

Good order (based on coverage):

Apollo → Hunter → Dropcontact → Clearbit

Mistake 4: Ignoring Regional Strengths

US-focused providers may have weak coverage elsewhere:

RegionBest Providers
North AmericaApollo, ZoomInfo, Clearbit
EuropeDropcontact, Cognism, Kaspr
APACApollo, Lusha, LeadIQ

Build region-specific waterfalls if your data is global.

Mistake 5: Not Tracking Provider Performance

Monitor which providers actually deliver value:

Provider Performance (30-day sample):

Apollo:     1,000 lookups, 580 found (58%)
Hunter:     420 lookups, 168 found (40%)
Dropcontact: 252 lookups, 88 found (35%)
FindyMail:  164 lookups, 41 found (25%)

Total: 877 emails from 1,000 records (87.7% coverage)

If a provider consistently underperforms, replace it.

Waterfall Templates

Here are copy-paste waterfall configs for common use cases:

Template 1: B2B Email Finding (US Focus)

Column 1: Apollo (Find Email)
  - Input: First Name, Last Name, Company Domain
  - Run: Always

Column 2: Hunter (Email Finder)
  - Input: First Name, Last Name, Domain
  - Run: When Column 1 is empty

Column 3: Dropcontact (Find Email)
  - Input: First Name, Last Name, Company Name
  - Run: When Column 1 AND Column 2 are empty

Column 4: Verified Email
  - Formula: COALESCE(Column 1, Column 2, Column 3)

Column 5: NeverBounce Verification
  - Input: Column 4
  - Run: When Column 4 is not empty

Template 2: Full Contact Enrichment

Column 1: Apollo (Enrich Person)
  - Get: Email, Phone, Title, LinkedIn
  - Run: Always

Column 2: Clearbit (Enrich Person)
  - Get: Email, Title, LinkedIn
  - Run: When Apollo Email is empty

Column 3: Hunter (Find Email)
  - Run: When Column 1 AND Column 2 emails are empty

Column 4: Lusha (Get Phone)
  - Run: When Apollo Phone is empty

Final Columns:
  - Best Email: COALESCE(Apollo Email, Clearbit Email, Hunter Email)
  - Best Phone: COALESCE(Apollo Phone, Lusha Phone)
  - Verification: NeverBounce on Best Email

Template 3: European Data (GDPR Compliant)

Column 1: Dropcontact (Find Email)
  - GDPR compliant, EU-focused
  - Run: Always

Column 2: Cognism (Enrich)
  - Strong EU coverage, compliant
  - Run: When Dropcontact is empty

Column 3: Kaspr (Find Email)
  - EU LinkedIn data
  - Run: When Column 1 AND Column 2 are empty

Column 4: Verification
  - MillionVerifier (EU-based)

Measuring Waterfall Performance

Track these metrics to optimize your waterfalls:

Coverage Rate

(Records with email found / Total records) × 100

Target: >80%

Provider Contribution

For each provider:
(Emails found by this provider / Total emails found) × 100

Use this to identify underperforming providers.

Cost Per Email

Total credits spent / Emails found

Compare across different waterfall configurations.

Verification Pass Rate

Verified emails / Total emails found

Target: >90%

If lower, you may have data quality issues upstream.

Integrating Waterfalls with Your CRM

Once you’ve built your waterfall, connect it to your CRM:

For Salesforce

  1. Use Clay’s native Salesforce integration
  2. Pull records needing enrichment (e.g., “Email is null”)
  3. Run your waterfall
  4. Push results back to Salesforce

Set this to run on a schedule (daily/weekly) to combat data decay.

For HubSpot

  1. Connect Clay to HubSpot
  2. Create a workflow that tags records for enrichment
  3. Pull tagged records into Clay
  4. Run waterfall
  5. Push enriched data back and remove the tag

You can also use Breeze Intelligence for simpler, real-time enrichment and Clay for deep batch enrichment.

When Not to Use Waterfalls

Waterfalls aren’t always the answer:

Skip waterfalls when:

  • You need real-time enrichment (use native CRM enrichment instead)
  • You only need one data type and one provider has great coverage
  • Your volume is too low to justify the complexity

Use waterfalls when:

  • Single providers give <70% coverage
  • You’re building prospecting lists from scratch
  • You need maximum data quality for high-value outreach
  • You’re enriching data for ABM campaigns