Sonoff Zigbee Smart Water Valve (SWV)

Just as I was pondering starting this Sonoff BSP review early July 2024, I saw Matt’s video (NotEnoughTech). Matt had a slightly different take on the SWV to what I’m about to share. He noted that the Zigbee2MQTT is not quite ready for the SWV (or vice-versa) (but see the end of this entry for update). I just updated my Zigbee2MQTT over the weekend. Also – see my Sept 2024 short Soonff/Shelly update and finally the update at the end here!!! I have the BSP version (British Standard Pipe fitting).

When Matt was working on his video, initially he had no garden – then it poured rain like crazy (well, he IS in the Northeast if England and of course rain in July is a regular feature there – something I know from decades of bitter experience). Matt set up the SWV to run on the Sonoff eWeLink APP, turning it on and off – and monitoring water flow. In the end that all worked well.

So how is my outlook different? I’m in the blazing heat of Southern Spain – no chance of rain here mid-summer… but I have a use for this device. I already have a plant watering system BUT we have an outside pool and every few days it needs a top-up due to evaporation (right now our humidity is VERY low and the sun is relentless) and guess what – I keep forgetting to turn the hose off – not a good idea right now.

I decided to write about the Sonoff Zigbee smart Water Valve. I opened the box, pulled out 4 AA batteries from my drawer and inserted them into the BSP.

The orange box you see in the photo (left) pulls out to let you insert AA batteries into it (I suggest decent alkalines). Importantly the box has a good seal. Next, I took the hose off my outside tap and fitted the SWV in-between the tap and the hose.

Up to now, all good. I decided to mate the SWV with the eWeLink App, forgetting that, being Zigbee, it would need to talk to a “hub”. First problem – I hit + on the APP which then asked me to scan the QR code on the BSP. Good idea – but in Spanish morning sunshine – erm, no.

I had enough trouble seeing my phone screen – and no way could its camera see the QR code on the side of the SWV. Sonoff put the QR code on the back of this black unit, in grey – and small – I suggest next release they may want to re-think the size and colour of the QR code? I also think (know) that will wear off in sunshine eventually so keeping a photo of the QR code is really a must.

At this point I thought “let’s try again”, took the SWV off the tap and hose and took it indoors (the unit was sopping wet). That’s when I twigged about the hub – I should know better of course. I can’t really use Sonoff hubs as I have a working installation with a Sonoff Zigbee USB dongle on my Raspberry Pi 5 which controls the house.

Never a good idea to try running two Zigbee hubs at once, so armed with having seen Matt’s video and happy that the unit works, turning water on and off and (reasonably accurately – 5-10%) measuring water flow, I set off to get the unit working with my Zigbee2MQTT.

A glutton for punishment, I took the unit back outside and re-fitted it to the tap and hose. To be sure it was still in pairing mode, I pushed the button on the side for 5+ seconds, noting the green light around the button, before retiring into my (air-conditioned) office.

I then went to my Zigbee2MQTT web interface (port 9099 by default) and told Zigbee2MQTT to accept new joins. Seconds later, the new unit showed up and I turned off the pairing in the Zigbee panel.

The unit is a good fit for my pretty standard outside tap (male connection on the tap) and hose (female connection on the hose), no leaks that I can find (that still applies weeks later – not a single leak). You can’t see the button (above right image – right hand side) but it’s big and well sealed – thumb size. A momentary press turns the water on or off with a satisfying click (and in the dark, a green flash). Note that Sonoff do supply a roll of white sealing tape, in my case not neaded.

Down to business: Knowing that my Zigbee2MQTT was happy with the SWV and I soon proceeded to my new Home-Assistant setup which immediately became aware of several new “entities” – “switch.sonoff_bsp” being the first and most obvious. I added a new tile to my HA dashboard.

Almost too easy. Of course, this is just the start, I’ll actually need a button that turns on the valve for a limited period of time before turning back off (done) – I’m not entirely insane and simply having a button that could be easily pressed, leaving the water flowing for hours-on-end would not earn me any brownie points.

This takes us to the two other important entities – which I put in my SENSORS dashboard. The first is a no-brainer (sensor.sonoff_bsp_battery), the second is (was) a problem (sensor.sonoff_bsp_flow) – looks good but initially did nothing – and Matt predicted this in his video. Battery reading – no problem…. flow, no…..

The flow sensor initially showed no history despite leaving the hose running while I wrote most of this blog entry (topping up the pool). We have rubbish water pressure here in rural Galera (Southern Spain) and to reliably top up the pool without periodically checking in, I need to know how much water has been put into the pool.

Of course I ALSO received the Sonoff SNZB-05P Zigbee water leak sensor so at a pinch I figured I could mount that upside down on the inside rim of the pool and use THAT to turn off the SWV – not ideal but another way to do it.

Important: Hours after enquiring, Sonoff responded to my email – they then fixed the FLOW issue with BSP and Zigbee2MQTT on the next release of the firmware – within a couple of days. Only time will tell how the Sonoff SWV stands up to Spanish sunlight – that wall where the tap is, takes a beating every sunny summer morning.

That morning I filled up a 12 litre water container (overfilled). The procedure took 1 minute 32 seconds. My maths isn’t up to it first thing in the morning so I asked ChatGPT for help….12 litres in 1m 32s – what is that in m3/h? – CHATGPT responded with approx 0.47 m3/h – and the SWV had stated the flow was 0.4 m3/h – considering I filled the unmarked bucket to the brim that all seems in order to me.

Note that over in the left image – I’ve added the SNZB-05P Moisture sensor – that’s had the lick-test several times over the last couple of weeks and seems to work perfectly – again a well sealed unit.

A quick Home Assistant automation would ensure the BSWV is turned off whenever water is detected by the SNZB-05P… If I had another SNZB-05P I guess I could tell when the water level is low enough to need a top-up (the opposite of leak detection) but that would imply permanently attaching the hosepipe to the pool – not going to happen.

Now as to whether that SNZB-05P uses up battery only on change or when submerged – Sonoff also just clarified that for me – no. 20ua typical whether wet or dry – wheeee. As it happens the BSP has proven trustworthy enough to leave the tap turned on and count on the SWV and Home Assistant to reliably turn water on and off as needed.

See my separate blog entry on moisture detection including the Sonoff and Switchbot units.

Udate December 2024

Some answers: Firstly, the QR code did not fade in the hot Spanish sun, secondly the batteries months later are just fine and lastly, I’m in the UK for Christmas and before leaving Spain I took the sensible step of removing the SWV from the outside tap and put it in the house for the winter, while wrapping some bubble-wrap around the outside tap. Note in the image above I called the unit BSP before being informed by one of you guys that BSP is just a British standard – oh, well, it works.

This morning I received an email from Sonoff to remind me that the unit is designed for 4c to 60c operation and should not be used in freezing conditions. Looks like I just beat them to it. It occurred to me tonight that an idea might be to add a function to an existing external temperature sensor to have it send an email alert or similar when conditions get down towards, say 5c to remind the owner to disconnect the unit until the weather improves. Worth a thought for anyone like me leaving the unit connected 24-7.

Overall, good gadget.