Most plumbing owners run this calculation once, get a number that feels manageable, and then spend a year wondering why the trucks are half empty. The formula they use is revenue goal, divided by average ticket, divided by close rate. It is the formula every agency blog publishes, and in a demand service trade it is wrong by roughly a factor of three.
The problem is not the arithmetic. It is that the formula assumes a lead is a conversation. In plumbing, most leads are ringing phones, and two things happen to a ringing phone before anyone gets a chance to close anything. It gets answered, or it does not. It gets booked, or it does not.
Here is the four gate version, with 2026 benchmarks, a worked example for a two truck shop, and the one fix that cuts the required lead count by 70% without adding a dollar of ad spend.
The short answer
Work backwards through four gates in this order:
- Jobs you actually need to source. Total jobs minus what repeat customers and referrals bring you unprompted.
- Booking rate. Sourced jobs divided by the share of answered calls your team converts into a scheduled appointment.
- Answer rate. Answered calls divided by the share of ringing phones your team picks up.
- Sanity checks. Does your dispatch capacity absorb the jobs, and does your marketing budget cover the leads?
Gates two and three are where the standard model breaks. They are also the only two you can move this month.
Why the usual formula undercounts by three times
The revenue divided by ticket divided by close rate model was built for quoted trades. A remodeler gets an enquiry, drives out, produces a bid, and wins or loses it. One conversion event, one close rate.
Demand service plumbing does not work that way. A homeowner with a sewer backup calls three numbers off Google in ninety seconds. Whoever picks up and books them gets the job, and the close happens on the phone rather than at a kitchen table.
ServiceTitan aggregated call data from more than 3,000 trade businesses and found the typical shop booked 42% of its calls. Plumbing came in highest of any named trade at 43% for June, ahead of electrical at 41% and HVAC at 38%. A model that assumes a 50% close rate and no booking gate is silently claiming your team performs better than the top of the industry at a stage it never measured.
By the numbers
Businesses with 25 or more technicians booked 59% of their calls. Businesses with fewer than five booked 24%. Two plumbing companies buying identical leads from the same platform in the same city convert them at rates that differ by a factor of 2.5, and almost none of that gap is about the leads.
That size gap is the single most useful number in this article, because it means your required lead volume is set by how you answer the phone, not by how good your market is. A one truck operator posting in r/smallbusiness in August 2026 sensed this without having the number, asking other plumbing owners for their real lead mix and noting that they would guess the right channel mix "shifts a lot between a 1-truck operation and a 5+ truck one." It shifts, and this is the mechanism.
Working example: a two truck shop
Take a residential flat rate shop with two plumbers targeting $1.2M a year, so $100,000 a month. Use a $600 average ticket, the figure a ServiceTitan panelist used for a typical service call.
| Step | Calculation | Result |
|---|---|---|
| Jobs needed | $100,000 ÷ $600 | 167 jobs |
| Less repeat and referral | 40% of total | 67 jobs |
| Jobs to source from marketing | 167 less 67 | 100 jobs |
| Naive model | 100 ÷ 50% close | 200 leads |
| Gate 2: booking rate at 24% | 100 ÷ 0.24 | 417 answered calls |
| Gate 3: answer rate at 65% | 417 ÷ 0.65 | 642 calls |
The simple formula said 200. The four gate model says 642. That is not pessimism, it is what the benchmarks describe: an answer rate in the 54% to 69% range that shows up across service industries, and a booking rate that small shops genuinely run at.
Assuming 40% of work arrives through repeat and referral is deliberately conservative. Jobber's 2026 home services research puts referrals at 59% of lead volume across the sector. If your referral share is stronger, subtract more, and your sourced number falls fast.
The budget check that kills the plan
Now price it. Local Services Ads run about $53 per lead for home services in SearchLight's 2026 dataset, and $59 for drain and sewer specifically. At 642 leads:
642 × $53 = $34,026 a month, against $100,000 of revenue. That is 34% of revenue spent on lead acquisition alone.
Profitability Partners, working from the P&Ls of home services companies between $2M and $30M in revenue, benchmarks plumbing marketing at 5% to 8% of revenue for a well run shop, 8% to 12% as acceptable, and anything above 15% as a red flag. A 34% plan is not aggressive. It is arithmetically impossible to fund.
This is the moment most owners conclude that leads are too expensive, or that their market is saturated, or that the agency is skimming. None of those is the problem. The lead number is unbuyable because it was calculated on top of a broken phone.
We build the lead plan backwards from your booking rate, your capacity and your job mix, so the number you get is one you can actually fund and actually dispatch.
The fix that beats a budget increase
Hold the goal constant at 100 sourced jobs. Change nothing about your ad spend, your channels or your market. Move the two gates.
| Scenario | Answer rate | Booking rate | Calls needed | Lead cost at $53 | % of revenue |
|---|---|---|---|---|---|
| Small shop default | 65% | 24% | 642 | $34,026 | 34% |
| Answer fixed only | 90% | 24% | 463 | $24,539 | 25% |
| Booking fixed only | 65% | 59% | 261 | $13,833 | 14% |
| Both fixed | 90% | 59% | 189 | $10,017 | 10% |
Going from 642 required leads to 189 is a 70% reduction, and it costs nothing in media. The 59% target is not aspirational, it is simply what shops with 25 or more technicians already achieve. Angie Snow, a ServiceTitan advisor and VP at Western Heating and Air, described her own company sitting in the 60s before it started measuring, and Black Diamond Plumbing and Mechanical near Chicago runs around 77%.
Tip
ServiceTitan's analysis found that a 5 percentage point improvement in booking rate is worth about $100,000 a year to a typical shop, and that it takes less than one additional booked call per weekday to get there. Not a new channel. One call.
The reason this lever is invisible is that nobody owns the number. A marketing agency reports leads delivered. A dispatcher reports jobs run. The gap between them is unclaimed territory, and it is where two thirds of a plumbing lead budget goes to die. Our breakdown of what plumbing leads actually cost covers the pricing side of the same problem.
Capacity sets the ceiling
Everything above answers how many leads you need. The opposite question matters just as much: how many can you physically use?
Profitability Partners puts a flat rate plumber at four to six service calls per day. At five calls a day across 21 working days:
| Trucks | Monthly job slots | Realistic at 80% utilisation |
|---|---|---|
| 1 | 105 | 84 |
| 2 | 210 | 168 |
| 3 | 315 | 252 |
| 5 | 525 | 420 |
The two truck example needs 167 jobs against 210 slots, so it runs at 80% utilisation. That works. A one truck operator running the same calculation discovers their entire business tops out around 105 jobs a month, roughly $63,000 in revenue at a $600 ticket, no matter how many leads they buy.
This is why buying volume before fixing throughput is destructive rather than merely wasteful. Emergency plumbing leads decay in minutes. A lead you cannot dispatch today is not banked for next week, it is a job your competitor ran and a review they earned.
Not all leads are leads
Two categories quietly inflate the count and deserve to be stripped out before you plan around it.
Quote work that never converts. A plumbing owner in r/Contractor in July 2026 described losing "10+ hours a week to dead end customers," driving to inspect renovation jobs, building quotes, and hearing nothing back. Those are leads by any lead vendor's definition. They are not jobs, and if they are inside your close rate denominator your close rate is understated while your lead requirement is overstated.
Leads you paid for and never touched. In February 2026 someone helping a plumbing business in r/smallbusiness called about 40 local service companies after 6pm and reported that only three or four had any system for catching the calls. Those calls were paid for. They rang. Nobody counted them because nobody heard them.
Both of these belong in gate three, not gate four. Fix the measurement before you fix the budget.
Calculate it per job type, not per company
A blended average ticket is the second silent error in the standard model. Blue Grid Media's 2026 plumbing benchmarks show what the blend actually hides:
| Job type | Cost per lead | Average ticket |
|---|---|---|
| Drain clearing | $30 to $50 | $125 to $300 |
| Toilet or fixture repair | $30 to $50 | $100 to $250 |
| Water heater install | $55 to $90 | $900 to $2,500 |
| Sewer line repair | $60 to $100 | $2,000 to $8,000 |
| Repipe | $65 to $110 | $4,000 to $18,000 |
The ticket range spans more than 50 times while the lead price barely doubles. Run the break even on the two ends and the verdict inverts.
A drain lead at $50. A $200 ticket at a 65% gross margin, which is the low end of the 65% to 75% target for drain and sewer work, produces $130 of gross profit. At a 40% booking rate your cost per booked job is $50 ÷ 0.40 = $125. The job nets about $5 before a dollar of overhead. At a 70% booking rate the same lead costs $71 per booked job and leaves $59.
A repipe lead at $110. An $8,000 ticket at a 50% gross margin produces $4,000. Even at a 20% booking rate, which project work deserves because it is quoted rather than dispatched, the cost per booked job is $550.
The expensive lead is the safe one. The cheap lead is the one that can quietly run at a loss, and it does so precisely in the shops with the lowest booking rates, which are the shops most likely to be buying on price. Note also that drain work is a front door rather than a destination: a $200 snake that surfaces a collapsed lateral is a different business than a $200 snake that ends there. Our guide to getting more plumbing leads covers which channels feed which job types.
Your number is not flat across the year
Volume planning by the month invites a nasty surprise in Q4. Blue Grid Media's seasonal table puts plumbing Local Services Ads cost per lead at $35 to $60 in October and $50 to $85 in December, with hard freeze events adding another 30% to 60% on top for the duration.
Take the fixed shop needing 189 leads. At October pricing that is roughly $8,978. At December pricing it is roughly $12,758, about 42% more for the same result. Plan lead spend in quarters, hold reserve for freeze weeks, and expect your cheapest acquisition months to be the shoulder ones when planned work replaces emergencies.
The six line worksheet
Run this once, on paper, with your own numbers:
- Monthly revenue target ÷ your average ticket = jobs needed.
- Minus repeat and referral jobs you get without paid acquisition = jobs to source.
- ÷ your booking rate (answered calls that become appointments) = answered calls needed.
- ÷ your answer rate (calls picked up ÷ calls received) = leads needed.
- × your blended cost per lead = monthly spend. Compare with 8% to 12% of revenue.
- Compare jobs needed with trucks × 5 × 21. If it exceeds capacity, you have a hiring plan, not a marketing plan.
If you do not know your answer rate and booking rate, stop at line three. Pull one week of call logs, classify every call, and compare it against booked jobs. That week of work will change the answer more than any channel decision you make this quarter.
The question behind the question
Owners who ask how many leads they need are almost always asking something else: why is the phone not producing enough work? Nine times out of ten the honest answer is not that the leads are too few or too expensive. It is that a quarter of them never got answered and three quarters of the answered ones never got booked, and the shop has been buying volume to compensate for a leak it never measured.
A one man operator in r/smallbusiness in August 2026 listed every channel he had tried after four years in business: BBB, Yelp, his Google page, Facebook ads, door hangers, car flyers, door knocking, private marketing firms, paid SEO, the chamber of commerce, and finally pay per lead, on which he had spent "more than most people make in a year in 2 years." The list is exhaustive and the conclusion he reached was that bigger companies simply outspend him. The benchmarks suggest something less bleak. Bigger companies book 59% of their calls and he is statistically likely to be booking 24%, which means at his current volume he is already buying between two and three times the leads he needs.
The number of leads you need per month is mostly a measure of how much waste sits between the ring and the truck. Shrink that, and the number gets small enough to afford.
Sources
- ServiceTitan, Data Report: Average Call Booking Rates: aggregated data from more than 3,000 trade businesses, June 2022 baseline; trade and shop size booking rate splits.
- Profitability Partners, Plumbing Profit Margins: P&L benchmarks from home services companies at $2M to $30M revenue and 200+ underwritten acquisitions; calls per plumber per day, marketing spend bands, departmental gross margins.
- Blue Grid Media, Plumbing LSA Cost Per Lead 2026: job type cost per lead and average ticket table, month by month seasonality, freeze event premiums.
- Plumbing SEO Agency, Plumbing Lead Generation Statistics: compiled SearchLight LSA and Google Ads benchmarks, answer rate range, Jobber referral share.
- r/smallbusiness, One Man Plumbing Business LLC and Growing A Plumbing Business, August 2026: operator accounts of channel exhaustion and truck count effects.
- r/smallbusiness, How are you handling calls when you're too busy to answer?, February 2026: after hours call coverage survey of roughly 40 local businesses.
- r/Contractor, How do you filter out tire kickers and time wasters?, July 2026: plumbing owner on hours lost to non converting quote work.