Plumbing Estimate Checks for Leaks, Drains, and Sewer Lines

How to compare scopes, avoid repeat repairs, and know what to ask before you approve the work.

Plumbing problems feel urgent because water damage spreads fast. A small drip under a sink can warp a cabinet base. A slow drain can turn into a full backup the moment someone takes a shower. And when a water heater quits midweek, the inconvenience is immediate.

The tricky part is that the “obvious” symptom is not always the cause. Homeowners often accept the first diagnosis they hear, approve a narrow fix, and then pay again when the real issue shows up a month later. A better outcome usually comes from one thing: a clear, written scope you can compare across providers.

In coastal regions and older neighborhoods (think aging pipes, shifting soil, tight crawl spaces, and mixed materials from decades of repairs), that clarity matters even more.

Below is a practical checklist to help you review plumbing estimates for leaks, drains, sewer lines, water heaters, gas lines, and repiping—so you can approve work with confidence.

Start with a short problem log

Before anyone arrives, write down what you’re seeing and when it happens. It sounds simple, but it can save diagnostic time and reduce guesswork.

Include notes like:

• Leak location and when it appears (morning, evening, only during use)
• Drain behavior (slow all the time vs. slow after heavy use)
• Odors (sewer smell near a sink, musty smell near a wall)
• Water pressure changes (sudden drop vs. gradual decline)
• Water heater symptoms (noise, lukewarm water, short hot-water runs)

If you can, take a few photos or a quick video. A plumber can often spot patterns you didn’t know to describe.

Know your shutoffs before you schedule work

Every home needs a basic “shutoff map.” If you don’t know yours, learn it before an emergency forces you to.

Make sure you can locate:

• Main water shutoff
• Water heater shutoff (water valve + gas valve or electrical disconnect)
• Fixture stop valves (under sinks and behind toilets)

If a valve is seized, mention that up front. A stuck shutoff can turn a minor repair into a longer, more expensive day.

Leak diagnosis: separate symptoms from the cause

A good leak estimate explains how the plumber will confirm the source—not just what they’ll replace.

Ask what steps they plan to take, such as:

• Visual inspection of supply lines, traps, and connections
• Moisture checks around cabinets, flooring edges, and wall penetrations
• Pressure testing when pressure feels high or fluctuates
• Isolation steps (shutting a fixture stop valve to confirm the source)
• Water meter movement checks when you suspect an underground leak

If the leak appears inside a wall or ceiling, ask two questions:

1. How will you limit drywall cuts?
2. How will findings be documented before opening more area?

A responsible scope describes the investigation plan and how the work area will be protected.

Drain clearing: match the method to the blockage

Not all clogs behave the same, and “clear drain” is too vague to compare.

Common approaches include:

Hand or power snaking

• Best for localized clogs near a fixture
• Often effective for hair and soap buildup in bathroom lines

Hydro jetting

• Better for heavy buildup and grease in longer lines
• Often used for recurring backups when pipe condition supports it

Video inspection

• Confirms root intrusion, offsets, broken pipe, or heavy buildup
• Helps you avoid repeated “clears” without proof of cause

What to require in writing:

• Which line is included (sink, shower, laundry, main line)
• How far they plan to go (distance, access points)
• Whether the estimate includes a camera inspection before or after clearing

A strong scope doesn’t just promise a result—it explains how they’ll verify the cause of the backup.

Sewer line work: insist on location, options, and documentation

Sewer problems can involve roots, broken clay, belly sections, or missing/blocked cleanouts—most of it hidden.

A solid sewer-line estimate should include:

• Cleanout location (or a plan to add one)
• Camera inspection notes and whether you receive photos or a recording
• The problem location identified by distance from the cleanout
• Repair options stated clearly (spot repair vs. lining vs. full replacement)
• A restoration plan for yard, driveway, or sidewalk disruption

If trenchless methods are proposed, ask what conditions make trenchless a fit—and what conditions rule it out. Get that in writing so you’re not surprised mid-job.

Water heater scope: treat it like a system swap, not “just a tank”

Water heater work often fails when the estimate only lists the unit and skips the supporting parts.

Ask the proposal to specify:

• Tank vs. tankless, plus fuel type
• Venting approach and any vent upgrades
• Seismic strapping (where required)
• Drain pan and drain line plan (especially in interior closets)
• Shutoff valve condition and replacement plan if needed
• Expansion tank plan when required by local conditions
• Disposal plan for the old unit

Also ask how access constraints are handled (tight closets, basements, garages) and whether the scope includes bringing the installation up to current safety standards where applicable.

Gas line work: demand clear safety steps

Gas piping is not the place for vague language.

If a scope includes gas work, it should state:

• Leak test method and verification steps
• Pipe sizing explanation tied to appliance load
• Valve location and labeling plan
• Permitting approach if the job triggers a permit

If you smell gas or suspect an active leak, prioritize safety: leave the area and contact your gas utility or emergency services. Estimates come after the hazard is controlled.

Repiping decisions: focus on symptoms and pipe condition

Repiping is sometimes recommended for homes with frequent leaks, chronic low pressure, or corroded pipe—but it should be justified, not rushed.

Ask for an assessment that includes:

• Pipe material identification (galvanized, copper, PEX, etc.)
• Pressure and flow concerns tied to diameter and condition
• Access plan (crawl space, attic, walls)
• Patch/repair plan after pipe runs, with clear boundaries
• Fixture connection plan (angle stops, supply lines, shutoffs)

Also ask about daily water shutoff windows and how service is restored each day—repiping impacts routines, and the schedule should reflect that reality.

Compare providers using scope clarity (not just price)

Estimates vary because companies define “included work” differently. One smart approach is to build your own checklist based on common service categories (leak detection, drain cleaning, sewer inspection, hydro jetting, water heater work, gas piping, etc.) and require each bidder to match it item by item.

Then compare proposals on specifics:

• Exact fixtures and lines included
• Diagnostic method listed (camera, pressure test, meter check)
• Parts list included (valves, traps, cleanouts, supply lines)
• Permit plan listed when required
• Restoration plan for drywall cuts or excavation
• Verification plan (pressure test, gas leak test, post-repair camera check)

A lower price isn’t a better deal if it excludes verification—or leaves restoration undefined.

Jobsite protection and communication expectations

Plumbing work can involve water, debris, and sometimes sewage exposure. A professional scope explains how the home will be protected.

Ask about:

• Floor protection in hallways and work zones
• Containment for dusty wall access work
• Cleanup plan for drain/sewer work (including disinfecting steps)
• Daily update routine for multi-day jobs
• Change-order proces when hidden damage is discovered

Clear communication matters most when the work affects bathrooms, kitchens, or your ability to stay in the home.

Homeowner checks after the plumber finishes

Before the crew leaves, do a quick walkthrough:

• Run each repaired fixture and check every connection for drips
• Flush toilets and watch the base for seepage
• Run hot water and confirm stable temperature
• Listen for water hammer or new vibration
• Recheck under-sink cabinets for moisture after 30 minutes
• Ask for a quick explanation of new valves, cleanouts, and shutoffs

Request copies of any tests performed (camera findings, pressure test results, gas test verification) when applicable.

Final takeaway

Plumbing problems rarely end with one part swap. The best outcomes come from three things: a diagnostic plan, a written scope you can compare, and a verification step that matches the symptom you started with.

If you approve work based on scope clarity—not urgency—you’ll usually spend less over time and deal with fewer repeat calls.

Disclaimer: This article is general information and not a substitute for professional diagnosis. For gas odors, suspected gas leaks, or major flooding, prioritize safety and contact the appropriate emergency or utility services.