Wired Everydrop flowmeter reading and app readings don't match

Accessories & Sensors Wired Flow Sensors
1

My neighbor and I installed the Rachio 3 back early December. We have since both installed the wired flowmeter. Both of our systems ran last night. My neighbor read the current value on the meter yesterday to compare with the app. I didn’t read mine last night but I did today so I can check with my app next run.

Anyway, the values do not match. Rachio has 1717 total and the flowmeter shows 1785. Granted this is only a 3.93% difference (67.5 gallons) but if Rachio is reading data from the meter, shouldn’t they match? And 67.5 gallons is significant.

As a side note, if you look at the calibrated flow for a zone and multiply that by the run time, you get a 3rd value that is even higher than the app or flowmeter.

As an example
GPM 11.9
Runtime 33 minutes
11.9 x 33 = 392.7

App said 324

When you do this for all zones, total calculated gallons is 2025.4. Very different from the 1717 and 1785 above.

2

There are more than several reasons that the volume shown on the face of the flowmeter vs. the volume shown as delivered by Rachio vs. the volume actually applied to your property may vary:

  • Controller settings for pressurization and settle times when starting and stopping runs. Whether pipes from the meter to the valve or from the valve to the sprinkler contain air or water and how long (and how many gallons) it takes to fill or empty the pipes.

  • Similarly, the length of those pipes. I have 8 zones and distances of from 20 to 100 feet, downhill, between the meter and the zone valves. It takes over 40 gallons of water to fill those pipes.

  • Whether you’re soaking while watering, particularly for zones on a slope, where the valve-to-sprinkler pipe is unpressurized and empties during soaking and must be refilled.

  • How accurately you’ve calibrated flow for each zone, including variations in pressurization at the time of day you calibrate vs. the time of day you water.

  • How accurately you’ve determined the zone parameters that will be used by Rachio to determine, along with the GPM reported by the flow meter, the water applied. One of the most important is the zone’s Area, which you should know accurately to calculate Precipitation Rate (see below).

It appears Rachio doesn’t require “real-time” flow meter input for Usage determination. The Baseline Flow calculated during calibration is used for the high/low flow alarm triggers and flow monitoring or shut off. The Advanced Nozzle Inches Per Hour setting appears to be used for backward-estimating usage when a contemporaneous determination of usage in a zone can’t be obtained from the flow meter. It’s not clear to me that Rachio re-calculates the Nozzle Inches Per Hour (Precipitation Rate) value, but just to be safe, I do the calculation myself when I re-calibrate and plug my results in the zone settings:

Precipitation rate (in/hr) = 96.25 x flow (gpm) / area (sq ft)

Your evaluation is very thorough. The only caution I’d suggest is that you’re working with too small of a sample. It’s early in the season and what seems like a significant amount of water (67.5 gallons?) is literally just a drop in the bucket. Get more info for a longer time - enough to at least find out that your water consumption, with better results, is substantially less (thousands of gallons) than your previous system, whatever it was. Once you and your neighbor get your systems tweaked, your other neighbors are going to want to talk to you.

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3

Thanks for the explanation. Your second bullet point doesn’t seem right. Wouldn’t the meter see the over 40 gallons needed to fill the pipes? And likewise with bullet 3 - soaking time and having to refill the pipe. All this water still goes through the flowmeter. Are you saying that the Rachio app doesn’t “see” this water? If so, any idea as to why?

We have Hunter MP heads where the PR is 0.4. This is the value I entered into the app. Looking at the data I compiled I can’t make sense of it either.

Zone 3
GPM 10.4
Run Time 41
Sq ft 2229
Available water 0.12
Root Depth 4
Allowed Depletion (%) 50
Efficiency (%) 80
Crop Coefficient (%) 65
Inches per Hour 0.4
App Gallons 386
Calculated gpm/ sq ft 0.1731

Zone 4
GPM 6.5
Run Time 41
Sq ft 949
Available water 0.12
Root Depth 4
Allowed Depletion (%) 50
Efficiency (%) 80
Crop Coefficient (%) 65
Inches per Hour 0.4
App Gallons 277
Calculated gpm/ sq ft 0.2392

Why are these different gpm/sq ft? Shouldn’t they be the same?

And regarding your comments about PR, are you suggesting that we use app gallons to get a different PR than the Hunter specs?

If so, Zone 3 would be 0.45 and zone 4 would be 0.66 (50% more than the spec for the heads). Now this assumes we measured the areas of the zones correctly. I’m not sure we did that because we have quite a lot of non-square / non-rectangle sections within each zone and the calculations for the odd shapes are most likely incorrect. I tried using Google but that was very difficult. And does one count the area into zone 3 where it throws water into zone 4? And then count that watered area into zone 4 as well if 4 throws water back into zone 3? This is what we tried to do.

4

All good questions, and you’re right about bullet 3 shouldn’t be related to the measurement of the water through the flow meter. I was trying to make 2 points at once, unfortunately, and soaking and refilling pipes, pressurization and settling are related to measures of Usage vs. real water applied to the zone.

I have some data on the EveryDrop 1004-EX (I’ve owned 3 of them) that suggests that EveryDrop’s accuracy vs. the curbside dedicated commercial water meter at my home is about ±2% from run to run. Over long (month) periods of time, Rachio is very accurate at reporting metered usage.

We plugged your data into our own calibration spreadsheet and got slightly different results:

Zone Minutes Gallons GPM Area PR
3 41 386 9.4 2229 0.41
4 41 277 6.8 949 0.69

There’s no such calculation as gallons per minute per sq. ft. The proper units of measure are inches of water per unit of time and the formula for that is:

Precipitation Rate (in/hr) = 96.25 x flow (gpm) / area (sq/ft)

You’re using 0.4 in/hr Hunter heads, which seems to indicate the flow over the entire zone 3 matches what you’d expect under every head, without any overlap. Zone 4 (0.69 in/hr), if it has the same type of heads, seems to put about 50% more water per area on the zone, suggesting there is more sprinkler density in that zone, more overlap. I don’t see any problems with that. Zone 4 is less than half the size of zone 3 and Rachio is putting water on it at a higher rate than the other zone. If the zones are the same type, when you have it tuned, Zone 4, getting more irrigation per square foot, should take less time to water than Zone 3, perhaps enough to be noticeable (occasional skips).

I’d encourage you take the time to precisely measure your zones - to the nearest square foot. If they’re irregularly shaped, do whatever you can to break a zone into smaller patches you can add together. If 2 zones are immediately adjacent (ie: there’s an overlap between the heads that cover the area between 2 zones), make a line right down the middle of that shared space to represent the boundary between the zones and measure them both using that boundary (ie: half of the overlap is assigned to each zone). You’ll only have to do it once.

If your zones 3 and 4 are growing grass, we’d think your root depth should be at least 6 inches - the depth you WANT your grass to get to. This may increase watering time but reduce watering frequency. You want to water grass well, infrequently. We think that Available Water is a bit low at 0.12, but you may have porous soil. The rest of your parameters seem pretty reasonable.

Finally, to answer the last part of your questions… Yes, it’s not the only way, but by doing your parameter setup and determining exactly how much water goes through the heads to the zones is the best reason you had for getting a flow meter in the first place. The type, or flow capabilities, of individual heads won’t matter. The water pressure in your neighborhood won’t matter. Calibrate with Rachio and the EveryDrop and make your schedules Flex Daily and you won’t have much to worry about. Good growing!

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5

Regarding gallons to sq ft, I was trying to see if the application of water was equivalent per zone. It isn’t.

So I guess you are recommending I change the PR in zone 4 to the 0.69 instead of 4? Is that how this should all work? And do this for each zone?

While I had tried Google earth before to do the measurements, it was extremely difficult. I did however find that the appraiser’s office in my area has a website where I found my property appraisal. It told me that the property was 13,506 sq ft. I looked at my house plans and determined the sq ft footprint of the house, lanai & driveway to be 4706 leaving 8800 sq ft for the yard. There was also a map on that webpage that you could click on. It opened a map of the area with property lines and tools to measure length and area. I redid all of my zones. Looking back at my hand sketch on a property drawing, I had made a couple of calculation mistakes. This map was a lot easier to use.

Anyway, the new total of all of my zones is 9339. This is 539 more sq ft (9339-8800). On that map, one side of my house has a shadow and it is hard to tell where the roof line actually ends so getting that area is tough. Also I have flowerbeds on 3 sides of the house that are wavy (not squared off and not straight lines). I took my manual measurement for that. But it makes getting the zone areas difficult because I can’t draw the wavy line. Now that I found the new map tool, I think I’m going to have to start over actually measuring my zones on paper and transfer it to that online map.

My neighbor and I have 6 zones with 1 being flower beds and 5 with St Augustine. Our soil type is sandy clay loam based on my jar test and the Multipoint Triangle. That is not a choice in the app and I posted here asking what to do. Someone said to use sandy loam in the app which gave the 0.12 as a default. St Augustine is supposed to get to 6 inch depth. I checked mine and it was between 0.5 and 1.5. I believe that was due to overwatering (amount and frequency) for almost 2 years. I would like to get it to 6 inches and thought since it is just now coming out of dormancy that 4 would be a good compromise. Once it gets there, I could change to 6. Didn’t want to over stress the grass. Am I thinking about this correctly? Or should I just change it to 6 inches now?

I did change to Flex Daily yesterday after adjusting the area of my zones. It made a huge difference in the scheduling of watering.

6

Yes. Enter the properly calculated Precipitation Rate for each zone as its Nozzle Inches Per Hour. Your flow meter will provide its own measure of how much water goes on each zone on each run. The setting value will be used to calculate Usage if the meter doesn’t provide it. (For users without a flow meter, this setting value needs to be accurate to determine application rates and make good Usage calculations.)

If you have a tape measure and a helper, you can probably measure all of the 6 zones in 30 minutes, without any documentation, maps or anything else.

If you’re growing St. Augustine or a garden, your root depth should be the depth you want your plants to go for water, not what they are now. Rachio will use the depth as a reservoir that it will keep from drying out, so the plants can thrive under conditions that require a reservoir that deep. You are going to train your grass to be tough and healthy. Your 4 inch depth is probably a good start, but if it never shows stress, increase it over time. Your grass needs a bit of stress to develop its roots. My St. Augustine, tended by a Rachio, a Tempest and an EveryDrop, in the hottest days of an East Texas summer, is watered no more than 3 times in a week, usually much less. There’s always water down there at 6" that it can use.

Sounds like you’re off and running. Good luck!

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7

Thank you. I’m using my personal Davis Vantage Pro2 weather station for data.

I had a helper with the manual measurements. I had good data points for the 1/2 way points between zones. I went back to the appraiser’s map and carefully re-drew the zones. I was able to draw in the non-square areas within the zones on the map so the calculations of area should be as best as can be.

I think I have very good area #'s now. I’m now within 41 sq ft of actual yard sq footage not covered by house, driveway, & lanai. This is about the best I can do.

Glad to hear I’m on the right track on “training” the roots to go deeper. I’ll recheck once a month and slowly increase depth in the app as I see they are going deeper.

8

You sound like me when I started this whole endeavor. Wondering why I had like 5% error rates on things, and trying to dial in the settings really precisely with catch cups and 10-15min run times and all that.
Then you get to mid summer and you see some grass/soil is a little drier, and other is growing mushrooms, and you just say screw the math and use empirical data to adjust each nozzle up or down 1, and each zone up to down a bit on Coeff, root depth, or allowed depletion to adjust flow rates. And you get your water bill and you keep trying to shorten the watering times or frequencies holding out an extra day for rain.

There’s a lot of things I wish were done better in the controller…like monitoring flow even when system isn’t watering to warn me of a leak. Or that my flow meter didn’t lose its total on power outage (I ended up putting my system on a UPS just for that reason–it was already there for my internet anyway).

9

Where are you seeing error rates?

I am trying to lower my water usage because with my Hunter controller, it only adjusted for rain using the rain sensor which are known to not be reliable, I know I over watered because my roots were not very deep and the grass just didn’t look healthy. I also have various types of weeds. Not large patches but still weeds everywhere.

My controller (even the Hunter) has always been on a UPS along with my internet router in the low voltage cabinet in the garage.

I bought catch cups but have only done 1 zone so far. I had 0.4 in the app because that was the specs on the Hunter MP rotors. The catch cup calculation was 0.38. I know my other zones are not 0.4 due to the area and the GPM and I have changed them all to the calculated PR.

Really hoping to lower my water bill but if it doesn’t and I have a lot healthier grass, I’ll be happier. I’d like a lush green yard.

My flow meter is about 4 ft from the valves so monitoring for a leak wouldn’t be that helpful to me. Now, if a valve was bad and allowing a little water through would show flow on the meter but as you say not the app. But with the addition of the optional in-app purchase of valve monitoring, I assume that would let one know there is an issue.

10

I saw the same discrepancy in numbers on the meter vs Rachio reported. Also numbers in catch cups vs Rachio or calculated (flow meter or nozzle / area watered).

I thought shallow roots was due to watering too often. Overwatering grows mushrooms, and water bills. Ironically, I spent a bunch of effort trying to learn the science of lawn care, and after 2 years, I completely flipped on how I think about it and do much less work. Less fertilizer, less herbicides, worry less about clover. In fact, my ideal lawn would be like 30% clover mixed with fescue very evenly. The grass near any clover patch looks SOOO much better all year.

11

At least be sure to enable this (Controller Settings / Flow Settings):

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Yea, but that’s still only monitoring just after a run. Completely ignoring the other 92%+ of the time that my trunk lines between valve boxes doesn’t leak.