Negative Keywords: The Google Ads Setting Wasting 20% of Your Budget

15-25% of the average home service contractor’s Google Ads budget goes to clicks that will never become customers. DIY homeowners looking for tutorials. Job seekers searching for plumber salaries. Students researching how to become an electrician. Google charges you the same $25-40 per click whether the person wants to hire you or just wants to watch a YouTube video.

A WordStream analysis of Google Ads accounts found that the average account wastes 20% of its budget on irrelevant search terms. For a contractor spending $3,000/month, that’s $600 going to people who were never going to call.

How irrelevant clicks happen

Google Ads uses keyword matching to decide when to show your ad. If you bid on “plumber” using broad match, your ad can appear for any search Google considers related. That includes “plumber salary,” “plumber training,” “DIY plumbing repair,” and “plumber tool kit.”

Each of those clicks costs you $15-40. None of those searchers need a plumber. But Google collected payment for every one.

Even phrase match and exact match aren’t bulletproof. Google has loosened match type definitions over the years. A phrase match keyword for “AC repair” might trigger your ad for “AC repair DIY tutorial” or “how to repair AC yourself.” Close enough for Google’s algorithm. Useless for your business.

An HVAC contractor on r/PPC pulled his Search Terms report after his first month on Google Ads and found that 31% of his clicks came from irrelevant queries. “HVAC technician salary” alone had cost him $340 in a single month. He was paying to educate job seekers instead of attracting homeowners.

The 5 negative keyword categories every contractor needs

1. DIY and how-to searches

People searching for how to fix something themselves are not hiring you. Add these as negative keywords immediately:

DIY, how to, tutorial, guide, step by step, do it yourself, fix it yourself, repair yourself, troubleshooting guide, instructions, video, YouTube

A plumber on ContractorTalk tracked his irrelevant clicks and found that “how to” queries accounted for 12% of his total clicks in the first 90 days before he built his negative keyword list. At $22/click, that was over $700/month in pure waste.

2. Jobs, salary, and career searches

These searchers want to become a contractor, not hire one. They’re the most common source of wasted spend:

jobs, hiring, salary, career, pay, wage, apprentice, apprenticeship, certification, license, training, school, degree, resume, interview, employment

3. Free and discount seekers

While not always bad leads, “free” searches generally attract price-shoppers who won’t pay professional rates:

free, cheap, cheapest, budget, discount, coupon, deal, bargain, low cost, affordable

Be careful here. “Free estimate” is legitimate search intent. Add “free” as a negative only in campaigns where it consistently produces low-quality leads, or use it at the ad group level to protect specific campaigns while allowing it in others.

4. Tools, supplies, and parts

People buying supplies are doing the work themselves:

tools, supplies, parts, rental, wholesale, distributor, supplier, Home Depot, Lowes, Amazon, buy, purchase, for sale

5. Reviews, complaints, and legal

These searches indicate someone investigating a company rather than hiring one:

reviews, complaints, lawsuit, scam, BBB, attorney, lawyer, sue

Building your negative keyword list

Start with the universal categories above. That gives you 50-75 terms on day one. Then grow the list weekly from real data.

The Search Terms report is your most important tool. In Google Ads, go to Keywords > Search Terms. This shows the actual queries people typed before clicking your ad. Every irrelevant query becomes a new negative keyword.

Review this report weekly for the first 3 months, then biweekly once your list stabilizes. Most contractors end up with 200-500 negative keywords that collectively save 20-30% of budget with zero impact on lead volume.

An electrician on r/sweatystartup described his process: every Monday morning, he spent 15 minutes reviewing the previous week’s search terms. Over 6 months, he built a list of 340 negative keywords. His cost per lead dropped from $180 to $112 without changing his bids or budget — purely by eliminating wasted clicks.

Negative keyword match types

Negative keywords have their own match types, and they work differently from regular keywords.

Negative broad match (the default) blocks your ad when all the negative keyword terms appear in a search, in any order. Adding “plumber salary” as a negative broad match blocks “salary for a plumber” and “plumber average salary” but not “plumber near me” (because “salary” isn’t in the search).

Negative phrase match blocks searches containing the exact phrase in order. “plumber salary” blocks “plumber salary 2026” but not “salary of a plumber.”

Negative exact match blocks only that exact query. “plumber salary” blocks only the search “plumber salary” — nothing else.

For most negative keywords, negative broad match is the right choice. It casts the widest net. Use phrase or exact match only when a broad negative might accidentally block legitimate searches.

Account-level vs. campaign-level negatives

Google Ads lets you apply negative keywords at the campaign level or through shared negative keyword lists across your entire account.

Account-level shared lists work best for universal negatives like DIY, jobs, and tools. Every campaign benefits from blocking these terms. Create a shared list called “Universal Negatives” and apply it to every campaign.

Campaign-level negatives work best for service-specific filtering. Your AC repair campaign might need “AC repair DIY” as a negative, but your general brand campaign doesn’t. Keep service-specific negatives at the campaign level where they’re relevant.

Common mistakes with negative keywords

Not having any. The most expensive mistake. If you’ve never added a negative keyword, you’re guaranteed to be wasting 15-25% of your budget right now.

Adding too aggressively. Blocking “repair” because some repair searches are DIY-related also blocks “emergency AC repair near me” — your best keyword. Be surgical. Block “AC repair DIY” and “AC repair tutorial,” not “repair” by itself.

Setting and forgetting. New irrelevant search terms appear constantly as Google broadens match types and search patterns change. A list that was current 6 months ago is missing dozens of new terms.

Ignoring the Search Terms report. Google doesn’t show you every search term — they hide a significant percentage under “other search terms.” But what they do show is enough to identify major waste categories. Check it regularly.

The budget impact

Consider a contractor spending $4,000/month with 22% of clicks going to irrelevant terms. That’s $880/month in wasted spend — $10,560 per year going to DIY searchers, job seekers, and tool shoppers.

Adding a comprehensive negative keyword list doesn’t reduce your lead volume. Those irrelevant clicks weren’t producing leads anyway. You keep the same number of leads and pocket the savings — or reinvest it into more of the keywords that actually convert.

A Redditor on r/PPC ran the numbers after 6 months of negative keyword optimization: his monthly spend stayed at $3,500, but his lead volume increased by 35% because Google’s algorithm could now focus budget on searches that actually converted. Removing waste didn’t just save money — it improved Google’s optimization signals.

For a full breakdown of Google Ads costs by trade, including how Quality Score interacts with negative keywords to drive down CPC, review the benchmarks. Understanding how marketing performance is measured ensures you’re tracking the right metrics as you optimize your negative keyword strategy.

Every dollar you stop wasting on irrelevant clicks is a dollar you can spend on a click that actually books a job.