Your Bluebot measures water without ever touching it. Two ultrasonic sensors sit against the outside of your pipe, sending sound waves through the pipe wall and the water inside, then timing how long those waves take to travel with and against the flow. That timing difference is your flow rate.

If the app reports no ultrasonic signal quality — a zero reading, not just a weak one — it means those sound waves aren't making it from one sensor to the other at all. The good news: this is almost always a placement or preparation issue, not a broken device. Here's how to work through it.

A zero signal usually means there's nothing for the sound to travel through.

Is it actually a water line? Bluebot will read zero on a gas line, because there's no water inside. Gas lines are typically black iron or galvanized steel. Water lines are usually copper, PVC, or PEX. If you're unsure, find your emergency shut-off valve — that's on your main water line.

Is the pipe full and pressurized? Bluebot needs a completely full pipe. A partially full line, a drain, a vent, or a line to a fixture that's been shut off won't give a reading. This is also why Bluebot can't go under a sink.

Is the main valve open? If water was shut off for a repair and not fully turned back on, you'll see nothing.

The sensors need solid, uninterrupted contact with clean pipe.

1. Clean the pipe properly. Paint, dirt, dust, cobwebs, and grime all block ultrasound. Use the sanding disk that came with your Bluebot to take the pipe down to bare material across at least 4 inches, then wipe it with the microfiber cloth — dampening the cloth helps.

2. Check the ultrasonic pads. If you tried a few locations before cleaning the pipe, the pads are probably dirty. Prop the clamps open with the C-holders, peel off both pads, and wash them with warm soapy water — or swap in the replacement pads. Peel one side of the new pad and press it over the clear plexiglass sensor window, then repeat on the other side.

3. Confirm a tight, snug fit. After clamping on, give the device a firm squeeze to close any gaps. A loose fit is one of the most common causes of a dead signal.

4. Check your alignment. The device must sit straight over the pipe, not at an angle. Use the "^" notches in the center of each side as your guide, lining up Bluebot's centerline with the pipe's centerline. To reposition, open the clamps and rock the device side to side to break the suction before pulling it off.

5. Make sure you have 4 inches of straight pipe. If the device is clamped over an elbow, fitting, or coupling, the sensors won't line up. Move further along the run. If there's no clear stretch outside near the shut-off, look indoors — the cold-water inlet near your water heater is often a good option.

If the pipe type selected during setup doesn't match what you actually installed on — say you picked copper but ended up on PVC — Bluebot will be calibrated for the wrong wall thickness and may read nothing.

To fix it: from the Dashboard, tap your device under Devices → Device Profile → scroll to Install Location → Pipe Type → confirm and select the correct type.

Then tap Rescan Pipe. This step is required. The rescan lets Bluebot re-measure and re-adjust itself to the new pipe, and skipping it leaves the device set up for the wrong material.

Hot pipes. Bluebot belongs on your main cold water line. Installing on the hot output from a water heater can melt the pads onto the pipe. If the device is stuck, hold the clamps open and gently rock it back and forth to break the suction — it should peel off. Then replace both pads. If you're installing outdoors in a hot, sunny climate, pour some cold tap water over the cleaned pipe before clamping on, and consider shading the device.

Scale and corrosion. If you have hard water and a home built before 1970, mineral scale or corrosion inside copper or galvanized pipe can effectively double the wall thickness. Sound can't get through. Try another section of pipe, or have a plumber inspect the line.

Also worth confirming: standard Bluebot fits pipes from 3/4" to 2". Larger sizes need a specially calibrated "prime" model.

If you've verified you're on a full, pressurized cold water line, cleaned the pipe and pads, aligned and tightened the device, corrected the pipe type, and rescanned — and you're still at zero — it's time for us to take a look.

Submit a support ticket at support.bluebot.com or call 1-888-258-4119. Have your pipe material, pipe size, and install location handy; a photo of your setup helps a lot. Our support team can walk through more advanced diagnostics with you.