Building a local prospect list from Google Maps

Step 1: extract the whole market, not the first page

Decide the categories your offer genuinely serves and the geography you can genuinely service, then extract completely inside those lines. A single Maps search stops around 120 results; grid extraction gets the real count. Run each category's main term plus its variants ("plumber" and "emergency plumber" surface different subsets), because Google's category matching is looser than it looks.

Resist trimming at this stage. The cheap moment to have complete data is now; every later step filters, and filters only work on rows you actually collected.

Step 2: clean on the right keys

1. De-duplicate on place ID, then on E.164 phone. Never on business name.
2. Drop permanently-closed listings. The single highest-value filter available.
3. Drop rows with no phone and no website. They cannot be contacted by any channel.
4. Normalise phones to E.164 so diallers, WhatsApp tools and duplicate checks all agree.
5. Stamp the extraction date on every row. Freshness is a property you prove, not assert.

Expect cleaning to remove 10-20% of raw rows. That shrinkage is the quality; a list that loses nothing in cleaning was not examined.

Step 3: segment before anyone touches it

Three cuts, in order of leverage:

• Review count. The best free qualification signal in local data. A business with 5 reviews and one with 300 differ in budget, maturity and what they will buy. Band them (0-10, 11-50, 51+) and pitch each band differently.
• Website presence. Rows with websites can enter email enrichment (expect 20-40% discovery); rows without belong to the phone cadence. Routing by this column is the difference between channel strategy and spray.
• Geography by coordinates. Cut territories on latitude/longitude clusters, not postcodes; businesses cluster around roads and centres, and coherent patches make call days efficient.

Step 4: ration the working segments

Hand out one to two hundred rows at a time, by segment, and release the next batch when the current one is dispositioned. Full-list access produces cherry-picking and burned leads; small segments produce coverage and honest feedback about which segment converts, which then reorders everything that follows.

Step 5: refresh on a schedule, and mine the deltas

Re-extract quarterly (monthly for high-churn categories) and diff against the previous pull. The deltas are their own prospect classes: new listings are businesses in buying mode for everything, closures keep your reps off dead numbers, and review-count jumps flag businesses investing in growth right now. A static list has none of this; the refresh cycle is where a Maps-built list permanently outruns anything bought. Export mechanics, including the Excel phone-number trap, are covered in the export guide.

The compliance line

Keep a suppression list from day one, honour opt-outs across channels permanently, and screen call segments against do-not-call registries where your market has them. The legality guide covers the fuller picture; the operational summary is that enforcement follows outreach behaviour, so the workflow above, worked politely, is also the compliant one.