Clay Waterfall Enrichment Recipe: How We Get 90%+ Email Coverage for B2B Outbound

You built the perfect ICP list. You nailed the targeting. Your copy is sharp. But when you run the campaign, half your emails bounce — because your data provider only had valid emails for 35% of your list.

Sound familiar? This is the single biggest reason outbound campaigns underperform, and it's entirely solvable.

In this guide, we'll walk through the exact waterfall enrichment recipe we use inside Clay to consistently hit 85-95% verified email coverage for our B2B clients — without burning through your budget.

What Is Waterfall Enrichment (and Why It Matters)

Waterfall enrichment is a method of querying multiple data providers sequentially to find a single piece of information — like a work email. Think of it like a cascading lookup: if the first provider comes back empty, you automatically try the next one, then the next, until you get a hit.

The concept is simple but the impact is massive.

Here's the core idea visualized:

How Waterfall Enrichment Works

Your Prospect List

Name + Company Domain

Provider 1 (Cheapest)

Icypeas

~40% found

Not found? Fall through

Provider 2 (Mid-tier)

Lead Magic

Findymail

FullEnrich

~30% more

Still empty? Final fallback

Provider 3 (Premium)

Better Contact

People Data Labs

Lusha

Datagma

~15% more

Email Verification

ZeroBounce

NeverBounce

MillionVerifier

Bouncer

Clean list

85-95% verified coverage

vs. 30-50% with a single provider

The magic of waterfall enrichment is that you only pay for successful lookups. If Provider 1 finds the email, you never hit Provider 2 or 3. This keeps costs down while maximizing coverage.

Why Single-Provider Enrichment Fails

Most B2B teams pick one data tool and assume they're covered. Here's why that breaks down:

• Coverage gaps are real. One provider might have strong coverage for US-based SaaS companies but miss European prospects entirely. Another excels at enterprise contacts but struggles with startups.
• Data decays fast. People change jobs every 2-3 years on average. Your provider's database is always partially stale.
• No provider is "best" across all segments. Each vendor has different data collection methods, geographic strengths, and industry focuses.

The numbers tell the story:

Email Coverage: Single Provider vs. Waterfall

Single Provider

~35%

35%

Two Providers

~65%

65%

Waterfall (3+ Providers)

~85-95%

90%

Based on aggregate data from 50+ Clay campaigns across B2B SaaS prospects

When we audit clients who come to us using a single provider, their actual verified email coverage (not just "found" — actually verified and deliverable) typically sits between 25-40%. That means more than half their TAM is invisible.

The Exact Waterfall Recipe We Use

Here's the step-by-step setup we deploy for every client engagement. This is battle-tested across 50+ campaigns.

Step 1: Import Your Prospect List into Clay

Start by creating a new Clay table and importing your prospects. You need at minimum:

• Full name (first + last)
• Company domain (e.g., stripe.com — not the company name)
• LinkedIn URL (optional but dramatically improves match rates)

Step 2: Set Up Your Provider Waterfall

This is where Clay shines. Click "Add enrichment" in your table, search for "Work Email", and select a pre-built waterfall — or build your own.

Here's the provider priority order we recommend:

Tier 1 — Budget

Icypeas

Lead Magic

Findymail

1-2 credits · Best for high-volume, general lookups

Tier 2 — Balanced

FullEnrich

Datagma

Prospeo

2-4 credits · Best for ICP-specific lookups

Tier 3 — Premium

People Data Labs

Better Contact

5-8 credits · Best for hard-to-find contacts

The key principle: cheapest providers first, premium providers last. You want to resolve as many lookups as possible at 1-2 credits before spending 5-8 credits on the hard-to-find contacts.

Step 3: Configure Conditional Logic

For each provider in your waterfall, set the run condition so it only fires when the previous provider returned empty. In Clay, this is a simple formula:

• Provider 2 runs only if Provider 1 email column is blank
• Provider 3 runs only if both Provider 1 and Provider 2 are blank

This prevents duplicate lookups and saves credits. Clay's pre-built waterfalls handle this automatically, but if you're building custom, double-check your conditions.

Step 4: Add Email Verification

This step is non-negotiable. After your waterfall finds emails, run them through a verification layer.

• ZeroBounce (built into Clay) — catches invalid, disposable, and catch-all addresses
• NeverBounce — alternative with strong catch-all detection
• MillionVerifier — budget option for high-volume lists
• Bouncer — fast turnaround with real-time verification API

Step 5: Filter and Export

After verification, filter your table to keep only verified and accept-all emails (discard invalid and unknown). Export to your sequencer (Instantly, Smartlead, etc.) or sync directly to your CRM.

The Real Results: What Coverage Looks Like

Let's be transparent with actual numbers from recent campaigns:

• Pre-waterfall (single provider): 28-45% verified email coverage
• Post-waterfall (3-provider setup): 82-93% verified email coverage
• Post-waterfall (5+ providers with phone fallback): 88-96% verified email coverage

The delta isn't just about more emails — it's about reaching decision-makers you literally couldn't contact before. When you're targeting a list of 500 VP-level prospects, going from 35% to 90% coverage means reaching 275 more people.

How Much Does It Actually Cost?

One of the biggest misconceptions about waterfall enrichment is that it's expensive. Let's break it down:

With Clay's credit-based model, you're typically spending $0.05-$0.12 per fully enriched prospect (email + verification). On the Explorer plan ($349/month with 10,000 credits), that supports roughly 800-1,200 fully enriched prospects per month.

Compare that to a $25,000/year ZoomInfo contract that gives you 40% coverage, and the math is obvious.

The BYOK Advantage

Clay lets you bring your own API keys (BYOK) for providers like Prospeo, Icypeas, Findymail, and many more. When you connect your own key, those lookups cost zero Clay credits. This is a massive cost-saver if you already have subscriptions to individual providers.

5 Pro Tips From Running 50+ Waterfall Campaigns

1. 1Test on a small batch first. Run your waterfall on 50-100 prospects before scaling. This lets you see credit consumption, match rates per provider, and catch any configuration issues without burning through credits.
2. 2Order by cost, not coverage. Your cheapest provider should always run first. Even if a premium provider has 5% better coverage, running it first wastes credits on lookups the budget provider would have found anyway.
3. 3Add LinkedIn URL as an input whenever possible. Match rates jump 15-25% when you include a LinkedIn profile URL alongside name + domain. Use Clay's LinkedIn enrichment to find URLs before running your email waterfall.
4. 4Set up monthly re-enrichment. People change jobs constantly. Set a Clay automation to re-run your waterfall monthly on CRM contacts where the email has bounced or the contact has been inactive for 90+ days.
5. 5Don't forget phone numbers. For high-value prospects (enterprise AEs, VPs, C-suite), add a phone waterfall as a secondary enrichment. Direct dials convert 3-5x better than email alone for enterprise outreach.

Common Mistakes to Avoid

• Skipping verification. We've seen teams send 10,000 emails from an unverified waterfall list and tank their domain reputation. Don't be that team.
• Using too many providers. More isn't always better. After 4-5 email providers, you hit diminishing returns. The coverage gains from providers 6, 7, 8 are minimal but the credit cost adds up.
• Not filtering by ICP after enrichment. Having someone's email doesn't mean they're a fit. Always apply ICP filters (title, seniority, company size) before sending.
• Ignoring catch-all domains. About 20-30% of B2B domains are "catch-all" — they accept any email address. These need special handling. Send to them in small batches and monitor bounce rates closely.

When to Use Waterfall Enrichment

Waterfall enrichment isn't for every use case. Here's when it makes sense:

• Outbound prospecting — When you need verified emails at scale for cold email campaigns
• CRM enrichment — Filling in missing contact data for existing leads and accounts
• Inbound lead enrichment — Automatically enriching form submissions with full profiles
• Account-based marketing — Building comprehensive contact lists for target accounts
• Event follow-up — Enriching attendee lists from conferences and webinars

The Bottom Line

Waterfall enrichment in Clay is the single highest-ROI investment you can make for your outbound motion. The setup takes about 30 minutes. The impact is immediate: 2-3x more reachable prospects from the same target list, at a fraction of what you'd pay for individual data subscriptions.

If you're still running outbound with a single data provider, you're leaving money on the table — and making your SDRs' jobs unnecessarily harder.

The best outbound teams don't have better copy or better timing. They have better data. Waterfall enrichment is how you get there.

FAQ

How many providers should I include in my waterfall?

For work emails, 3-5 providers is the sweet spot. You'll capture 85-95% of available emails with diminishing returns beyond that. For phone numbers, 2-3 providers is usually sufficient since the provider landscape is smaller.

Does waterfall enrichment work for European prospects?

Yes, but coverage rates are typically 10-20% lower than US prospects. European data providers (like Icypeas and Datagma) should be prioritized in your waterfall for EU-focused campaigns. GDPR compliance is handled at the provider level — Clay aggregates but doesn't store raw data.

How often should I re-run my waterfall?

For active outbound lists, monthly re-enrichment catches job changes and new data. For CRM maintenance, quarterly is usually sufficient. Set up Clay automations to trigger re-enrichment when emails bounce or contacts go inactive.

Can I use waterfall enrichment with my existing CRM data?

Absolutely. This is one of the most common use cases. Import your HubSpot or Salesforce contacts into Clay, run the waterfall to fill in missing emails and phone numbers, then sync the enriched data back to your CRM.

What's the difference between Clay's pre-built waterfalls and custom waterfalls?

Pre-built waterfalls are ready-to-use sequences Clay has optimized for common data types (work email, phone, personal email). Custom waterfalls let you pick your own providers, set the order, and add specific conditional logic. We recommend starting with pre-built and customizing once you understand your coverage patterns.