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TDSBot for car wash water quality
Real-Time TDS Monitoring for Spot-Free Rinse Water
TDS above 10 ppm leaves spots. TDSBot monitors your tunnel or in-bay RO output every minute and alerts before the first car is touched.
RO + DI output monitorUpdated every hour
Tap a tab above to see readings change
4.2ppm
RO permeate TDS · current reading
Spot-free · within spec
RO outlet4.2 ppm
Alert level10 ppm
Reject ratio97.3%
RO membrane performing normally. Output 4.2 ppm — safe to wash. All surfaces will rinse spot-free.
For Wash Owners
One silent RO failure on a Saturday costs more than three years of TDSBot.
Your membrane degrades invisibly — by the time spotted cars are leaving the wash you've already lost the day: refunds, reputation, emergency call-out.
<10
ppm TDS for spot-free — no exceptions
$24
TDSBot Monitor cost per year
For Operations Teams
Stop guessing when the RO failed. The data has a timestamp.
TDSBot logs every minute of RO output: TDS, reject ratio, flow rate. You know exactly when quality crossed the threshold, not just that it did.
1 min
Measurement interval
97%+
Reject ratio tracked — membrane health visible
For Multi-Site Fleets
Twelve wash locations this morning. Was the water spot-free at all of them?
One failed RO at one site means every car washed there today comes out spotted before anyone notices. TDSBot monitors every location and sends an alert before the first car enters out-of-spec water.
All sites
Fleet dashboard — every location, one view
0
Sites running blind when every RO is monitored
The science of pure water cleaning
Why TDS below 10 ppm.
No exceptions.
Most spot-free rinse systems use two stages: an RO membrane for bulk rejection, then a DI resin cartridge that polishes output to near-zero TDS.
Water below 10 ppm is undersaturated — it actively strips mineral deposits from the surface on contact, and when it evaporates it leaves nothing behind. The higher the TDS above 10 ppm, the worse the spotting.
At 35 ppm
35ppm
Ca²⁺, Mg²⁺ and Na⁺ present in solution. When the water evaporates those ions crystallise on the surface — white deposits are visible to the naked eye at 20 ppm and above.
On the surface
Spots on black paintwork and glass after evaporation. Complaints, refunds, reputation damage.
At 4 ppm
4ppm
Virtually no ions present. The water is chemically attracted to mineral deposits on the surface — it actively cleans, and evaporates leaving nothing behind.
On the surface
No residue. Spot-free finish on every surface, and the next wash date does not move forward.
RO rejection required (95–98%) → DI polish to <1 ppmTwo-stage
What a silent RO failure costs
Two hours. One silent failure. The difference TDSBot makes.
RO and DI failures are silent. Without monitoring, the first signal is a customer complaint after 80–120 vehicles are already spotted. Then come refunds, re-washing, and an emergency call-out.
Without TDSBotSilent failure
Example · 2-hour failure · 60 cars/hour · $15/car
$1,800 in refunds
Plus re-wash labour, reputation damage, Google reviews
06:00Wash opens. RO output: 28 ppm — membrane at 86% rejection. Nobody knows.
06:00First vehicles wash with out-of-spec water. Spots forming on paint and glass.
07:45First complaint call. Customer returns with a spotted car.
08:00Operator checks TDS manually: 28 ppm. Wash halted.
14:00RO technician arrives. Membrane replaced. Wash reopens 8 hours late.
120 vehicles spotted$1,800+ refunds · 8hr closure
With TDSBotCaught early
With TDSBot · alert at threshold breach
$0 in refunds
Wash halted before the first vehicle. RO serviced. Reopened same day.
03:20TDSBot detects RO outlet rising — membrane degrading. Reject ratio: 91%.
04:45Outlet TDS reaches the 10 ppm alert threshold. Email alert sent to the operator.
05:30Operator calls the RO service company. Technician booked for 6am arrival.
06:00Wash opens 45 minutes late. Membrane replaced before the first vehicle.
06:45RO output: 3.8 ppm. TDSBot confirms spot-free. Normal operation resumes.
0 vehicles spotted45min delay · $0 refunds
How TDSBot installs
Two configurations, whichever wash you run
Fixed installation
Tunnel wash — one RO, continuous monitoring
TDSBot installs permanently inline on the RO permeate line, between the membrane and the distribution manifold feeding the rinse arch. Monitors continuously, 24/7. A second sensor on the feed water inlet adds dual-sensor reject ratio tracking. Connects to your site WiFi.
S1: Post-DI outlet · alert at >5 ppm (spot-free)S2: Post-RO / pre-DI · tracks DI resin exhaustionInstall: 1/4″ quick-connect fitting · 20 minutes
Multi-bay installation
In-bay automatic or self-serve — one RO, multiple bays
Self-serve and in-bay automatic sites often run a single shared RO feeding a spot-free rinse manifold across several bays. TDSBot installs at the shared RO outlet, so one sensor covers every bay drawing from it — no need to instrument each bay unless bays run independent RO units.
S1: Shared RO outlet · covers all connected baysS2 (optional): Per-bay, if bays run independent ROAlert: Same threshold logic, one dashboardInstall: 1/4″ quick-connect fitting · 20 minutes
Membrane health over time
Degradation is gradual. Failure is sudden.
At 97% rejection: 6 ppm — spot-free. At 85%: 30 ppm — complaints. DI resin exhausts separately. Neither failure is visible to the eye.
TDSBot sees the trend crossing 10 ppm weeks before a complaint. Planned service, not a Saturday emergency call-out.
6 ppm
Outlet TDS at 97% rejection (new membrane)
30 ppm
Outlet TDS at 85% rejection (spotting occurs)
TDSBot detects the rejection trend falling weeks before it crosses the 10 ppm threshold
Schedule a planned membrane service instead of an emergency Saturday call-out
Dual-sensor reject ratio distinguishes membrane degradation from bypass valve drift or a feed pressure drop
RO outlet TDS · 16-week trend
W1–W10: 3–7 ppm — membrane healthy, spot-free output
W11: TDS rising — rejection falling below 94%. TDSBot tracking the trend.
W12: TDSBot alert fires at 10 ppm. Service booked. Wash continues on backup RO.
W15 (without TDSBot): 32 ppm — first customer complaint. Emergency call-out.
We had a membrane fail on a Friday afternoon and didn't find out until Monday morning — 400 cars washed over the weekend with 28 ppm water. The complaints were still coming in on Wednesday. TDSBot would have fired an alert within 20 minutes of the threshold breach. We installed it the week after.
Pricing
Hardware + software.
One straightforward price.
Buy the sensor once. Plans are chosen in the app after your TDSBot arrives — upgrade, downgrade or switch anytime, no lock-in.
TDSBotStandard
$59one-time
Hardware · one-time
No display — readings via app & dashboard1/4″ inline flow meter2× conductivity + temperature probesWiFi + Bluetooth (BLE)Micro-USB poweredIndoor use · quick-connect fittings
Order TDSBot
TDSBot DisplayWith display
$69one-time
Hardware · one-time
LCD display — live TDS visible at the unit1/4″ inline flow meter2× conductivity + temperature probesWiFi + Bluetooth (BLE)Micro-USB poweredIndoor use · quick-connect fittings
Order TDSBot DisplayBigger lines
3/8″ · 1/2″ · 3/4″ · 1″
Larger flow meter sizes for commercial tunnel washes, industrial RO systems and high-flow installations.
Data plans
What the sensor sends,
and how often
All three plans measure every minute — what changes is how often data leaves the sensor, and which analysis runs on it.
Monitor
$2/device/mo
Billed monthly or annually (−15%)
Every minuteDaily uploadEmail alerts
TDS, Temperature, Flow — every minute
Threshold alerts when exceed your set levels
Predictive filter depletion (configurable, default 30 days)
Daily pass/fail status report
Multi-site fleet dashboard — corporate → store hierarchy
Full log per filter cycle — resets when filter/RO membrane is changed
ESG report
Protect
$3/device/mo
Billed monthly or annually (−15%)
Every minuteHourly uploadEmail alerts
Everything in Monitor +
Hourly upload
Data-driven filter change scheduling
LSI + Larson-Skold @25°C, 93°C and 130°C
Estimated hardness + cumulative hardness load
Full log per filter cycle — resets when filter/RO membrane is changed
Pro
$7/device/mo
Billed monthly or annually (−15%)
Every minuteHourly uploadEmail · WhatsApp soon
Everything in Protect
Multi-site fleet dashboard with LSI / LS view
Corporate → site hierarchy — ops team sees all, baristas see theirs
Monthly ESG water report — liters filtered, cartridges saved
Full log per filter cycle — resets when filter/RO membrane is changed
Everything included — no add-ons, no per-feature upsells.
Common questions
Before you install,
the straight answers
Most spot-free rinse systems use two stages: an RO membrane (bulk rejection, 90–98%) followed by a DI resin cartridge that polishes output to near-zero TDS. Water below 10 ppm is undersaturated — it actively strips mineral deposits from the surface on contact, and when it evaporates it leaves nothing behind. Above 10–15 ppm, dissolved calcium, magnesium and sodium crystallise into visible spots as the water evaporates on paintwork or glass. The higher the TDS above 10 ppm, the worse the spotting.
TDSBot uses a dual-sensor configuration: one sensor on the feed water inlet, one on the permeate outlet. The reject ratio — (TDS_inlet − TDS_outlet) / TDS_inlet — gives continuous membrane health data. A healthy membrane achieves 95–98% rejection, producing sub-10 ppm output from typical mains water. As the membrane ages or fouls, rejection falls and outlet TDS rises. TDSBot alerts before a single car is washed with out-of-spec water.
A wall-mounted meter shows you the reading when you look at it. TDSBot shows you the reading every minute and alerts you when it changes. The failure mode of a wall meter is human — someone forgets to check it, or checks it at 8am and the membrane fails at 10am. TDSBot monitors continuously, 24/7, and sends an alert the moment output TDS exceeds your threshold. You do not have to be there, and you do not have to remember to check.
With a single outlet sensor it cannot — both membrane degradation and insufficient feed pressure increase outlet TDS. With dual sensors (S1 on feed, S2 on permeate), TDSBot calculates the reject ratio. If the reject ratio falls, the membrane is degrading. If the ratio holds but outlet TDS rises because inlet TDS has risen (a seasonal source change, for example), the membrane is fine and the source water is harder. Dual sensor is recommended wherever diagnosing the cause matters, not just detecting the symptom.
TDSBot uses quick-connect fittings that work with 1/4″ to 1 1/2″ water lines. In a tunnel wash the sensor installs on the RO permeate line — between the membrane housing and the distribution manifold feeding the rinse arch, typically accessible in the plant room and away from direct spray. Installation takes 15–20 minutes and does not require shutting down the whole wash, just a brief interruption to the RO line. Mount it in the plant room or another dry, enclosed spot — it is not rated for hose-down or outdoor exposure.
10 ppm is the standard threshold for most spot-free applications. With a post-RO DI cartridge, output is typically 0–2 ppm when healthy — set the DI alert at 5 ppm to catch resin exhaustion early. In practice many operators set a warning at 8 ppm (approaching threshold, plan maintenance) and an alert at 10 ppm (halt wash, service required). You set your own threshold at onboarding and can change it at any time in the dashboard.
Know your water is spot-free
before the first surface is touched
TDSBot installs in 20 minutes. Alerts within minutes of a threshold breach. The cost of one prevented silent RO failure pays for decades of monitoring.
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Disclaimers: TDSBot measures TDS, conductivity, temperature and flow rate directly. LSI, Larson-Skold Index, hardness and alkalinity estimates are derived from onboarded utility water chemistry data — not directly measured inline. TDSBot does not measure PFAS, bacteria, or other biological or chemical contaminants; for RO systems, reject ratio is used as a proxy indicator of membrane performance only. TDSBot monitoring data is not a substitute for accredited laboratory testing or statutory water quality compliance testing. All third-party brand names are trademarks of their respective owners; WaterTDS Inc. claims no affiliation, endorsement or partnership unless separately announced.
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TDSBot® · PWSID cross-referenced · EPA SDWIS · SCA Water Standards