Most bad plumbing estimates are not arithmetic failures. They are memory failures. Something was visible on the day, nobody wrote it down, and it became a cost later.
Two checklists follow. The first is for the visit, the second is for the five minutes before you press send.
At the site visit
The problem itself
- What the customer says is wrong, in their words
- What you observe is wrong, which is often different
- How long it has been happening, and whether anyone has worked on it before
- Whether it is getting worse, which changes their urgency and your scheduling
The system
- Supply material and apparent age: copper, PEX, CPVC, galvanised, polybutylene
- Drain material and configuration
- Water pressure at a hose bib, and whether there is a PRV
- Main shut-off location, and whether it holds
- Water heater age, capacity, fuel and condition, even when that is not the job
- Any evidence of previous leaks or previous repairs
Access
- How you physically reach the work
- What has to be moved, opened or protected
- Whether the space takes one person or two
- Parking, and how far material has to be carried
- Pets, alarm codes, gate codes, and who is home
Code and permit
- Jurisdiction and permit cost
- Inspection lead time, which affects your schedule more than your price
- Anything the work triggers as an upgrade
The customer
- Who is actually deciding, and whether they are present
- Whether it is owner occupied, rented or being sold, which changes what they will spend
- Timeline
- Whether they have other quotes
Always
- Photographs of the work area, the connections, the shut-off and anything you are excluding
The one question worth asking every time: "Is there anything else in the house that has been annoying you?" It is not a sales tactic, it is how you find the second job that is genuinely worth doing while you are already there.
Before you send the quote
- Does the scope describe the outcome in language the customer would recognise, rather than trade shorthand?
- Is every material on the list? Check against an assembly, not against memory.
- Are the hours realistic for this house rather than for the easy version of this job?
- Is drive time and the supply house trip in there?
- Is labour at loaded cost rather than at wage?
- Is overhead applied?
- Is margin applied as a divisor rather than added as a percentage?
- Are the exclusions written down? Particularly anything behind a finished surface.
- Is the permit position stated?
- Is there an expiry date?
- Is the warranty split between equipment and labour?
- Could a competitor read your labour rate off it, and do you mind?
- Would it survive the job taking one extra hour? If not, it is priced too tightly.
Points five, six and seven are where most of the lost money is. The markup and margin calculator makes the divisor point obvious in about ten seconds, and the overhead rate calculator gives you the figure for point six.
After it is sent
- Note the date, so you know when to follow up rather than trying to remember
- Follow up at least three times. Most accepted quotes are accepted after the second contact, and most plumbers stop at one
- Record why the lost ones were lost. Price, timing and "went with someone else" are three different problems with three different fixes
A ready-made sequence is in the follow-up sequence builder if writing them is the part that does not happen.
General guidance. Permit requirements, licensing and what must appear on a written estimate vary by state.
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