Water · plumbing

RV holding tank sanitation

Bad sensor readings, odor, and sticky solids make up most sanitation calls. Almost all of it comes down to water volume, treatment honesty, and never dumping illegal.

Active corridor: Montana · Wyoming · Idaho · Washington — case-by-case beyond.

Field notes

Corridor camps and boondock nights mean tanks sit. Black tanks need enough liquid and the right treatment so solids do not pyramid under the toilet. Gray tanks collect food grease and soap scum that foul sensors just as hard.

Who this is for

Right place if you

Fight odor at the toilet, see false “full” sensors, or inherited a coach with unknown tank history.

Black vs gray reality

Black tank

Keep liquid above solids. Flush with adequate water after each use. Treat after a dump when the tank is mostly empty so product contacts walls, not a solid plug.

Gray tank

Grease and soap build film. Hot water and enzyme products help; harsh solvents can damage seals and sensors — skip garage chemistry.

Sensor fouling

Probes and strips read wrong when coated. Cleaning methods that do not destroy sensors matter — see tank sensor troubleshooting.

Legal dump only

Use designated dump stations or sewer hookups. Never dump roadside, in storm drains, or on private land without permission. Illegal dumps are a health and legal problem — not a shortcut.

Enzyme vs chemical honesty

Enzyme and bacterial treatments break down waste when temperatures and dwell time cooperate; they are gentler on seals and sensors. Formaldehyde-style chemicals knock down odor fast but can be restricted at some dumps and are harder on the system — check local rules. No product replaces water volume or a proper rinse after dump. Ignore miracle “never dump” claims.

Owner checklist

  • After dump: black-tank rinse if equipped; leave a few gallons of water plus treatment
  • Use toilet paper rated for RV or septic; avoid wipes in the black tank
  • Gray: scrape plates, use sink strainers, avoid pouring grease
  • Vent clear — odor often is a vent or seal issue, not “empty the bottle of scent”
  • Gloves and eye protection at every dump; rinse hose fittings before stowing

DIY vs Prefer Text

Reasonable DIY

Routine treatment, careful dumps, sensor flush with manufacturer-safe cleaners, seal inspection.

Book us when

Stuck solids, broken valves, persistent odor after correct process, or winterize/trip-prep needs. Prefer Text symptoms and tank type (cassette vs permanent).

FAQ

Why does it smell inside?

Dry P-traps, bad toilet seal, clogged vent, or overfull black tank. Fix the path, not only the fragrance.

Can I use household drain cleaner?

Generally no — risk to valves, seals, and sensors. Stick to RV-labeled products.

Sensors always full?

Usually fouling, not a dead board. See the sensor guide before replacing the monitor panel.

Service quote?

Prefer Text — trip and labor as listed below; we do not invent tank-product SKUs on the phone.

Related: Dump station · Tank sensors · Toilet systems · Fresh tank sanitize

Pricing teaser

Trip fee $75 within 30 miles, then $1.50/mi each way. Labor ~$150/hr (1-hour minimum, billed in 30-minute increments). Diagnostic $175 applied toward repair if you proceed.

Credentials (text): Victron Professional Certified Installer · weBoost Authorized Installer · Peplink Certified Associate · Dometic Professional Certified. Starlink = installs only (not a certified partner title).

Prefer Text Book a Service