The table below is an adjusted version of my water consumption for the last five years (units are in CCU Ft. [CCU = hundreds of cubic feet]). I say adjusted because there have been a number of notable events that have occurred which have distorted the "real" usage. We had a malfunction in 2011 when we were in Europe for two months which caused excessive watering, and we had a "blow-out" in our system caused by excessive water pressure in 2010. In both instances the water company has "adjusted" our usage as an accommodation. Yellow highlight in the chart below are readings since I started water conservation efforts
Jan-Feb Mar-Apr May-Jun Jul-Aug Sep-Oct Nov-Dec Total
2014 32 10 78 79 77 13 289
2013 7 31 113 117 95 43 406
2012 9 14 83 116 84 14 320
2011 8 9 84 93 90 33 317
2010 5 6 69 89 89 26 284
2009 8 20 89 82 121 6 326
Avg. 11.5 15.0 86.0 96.0 92.4 22.5 323.7
What is not reflected in the table above is a leak that developed starting in about April, 2013 and lasted until January, 2014.
I have created a further nominally adjusted water usage for the last five years reflecting this additional leak as follows:
Jan-Feb Mar-Apr May-Jun Jul-Aug Sep-Oct Nov-Dec Yearly
2014 8 10 78 79 77 13 265
2013 7 10 83 93 87 22 302
2012 9 14 83 116 84 14 320
2011 8 9 84 93 90 33 317
2010 5 6 69 89 89 26 284
2009 8 20 89 82 121 6 326
Avg. 7.5 11.5 81.0 92.0 91.3 19.0 302.3
This next table is the same as above with projected numbers in red and the tier level in either Blue, Green, Orange, or Yellow corresponding to I, II, III, IV.
Jan-Feb Mar-Apr May-Jun Jul-Aug Sep-Oct Nov-Dec Total
2015 5 6 70 70 70 10 231
2014 8 10 78 79 77 13 265
2013 7 10 83 93 87 22 302
2012 9 14 83 116 84 14 320
2011 8 9 84 93 90 33 317
2010 5 6 69 89 89 26 284
2009 8 20 89 82 121 6 326
Avg. 7.5 11.5 81.0 92.0 91.3 19.0 302.3
2013 2013 2013 2013
Actual RED Total % by volume cost % by cost
Tier I BLUE 116 38.41% $387.44 16.14%
Tier II GREEN 103 34.11 770.44 32.10%
Tier III ORANGE 83 27.48 1,242.51 51.76%
Tier IV YELLOW 0 0.00 0.00 0.00%
Total 302 100.00 2,400.39 100%
Below are the actual 2014 water consumption numbers.
2014 2014 2014 2014
Projected RED Total % by volume cost % by cost
Tier I BLUE 109 41.13% $407.66 20.37%
Tier II GREEN 99 37.36 740.52 37.00%
Tier III ORANGE 57 21.51 853.29 42.63%
Tier IV YELLOW 0 0.00 0.00 0.00%
Total 265 100.00% 2,001.47 100.00%
Below is the actual difference between 2013 and 2014.
Difference 2013 - 2014
Projected RED Total % by volume cost % by cost
Tier I BLUE 7 -2.72% $-20.22 -4.23%
Tier II GREEN 4 -3.25 29.92 -4.90%
Tier III ORANGE 26 5.97 389.22 9.13%
Tier IV YELLOW 0 0.00 0.00 0.00%
Total 35 398.92
I started daily monitoring of the water consumption on February 1, and will keep a current log on-line on a bi-monthly basis starting with the March/April usage.
Note that all tier III water is used during the 6 month period from May to October. Further note that for 2013 while only 27.48% of the volume of water is from Tier III, 51.76% of the cost is attributable to this use. This is a total of 83 CCU of water, approximately 62,000 gallons of water during the 6 month period.
I understand that by reducing the water pressure from 50 lbs. to 30 lbs. will make the sprinklers operate more efficiently and reduce the misting and evaporation of water by at least 25%. This would reduce the water need to about 46,000 gallons.
It is my hope that I will be able to use the stored rainwater that exists in the tanks starting on April 13 of each year to offset this Tier III water use. I think that having the tanks full on that date will not be difficult to achieve.
I estimate that I water the landscape about twice a week, or 18 times per bimonthly period. I will deal with conservation of water use elsewhere. Each cycle is about 3,500 gallons, which comes to about 64,000 gallons. Of these 64,000 gallons 59 CCU or 44,100 gallons are Tier I and Tier II water, leaving about 20,000 gallons of Tier III water to conserve for each bimonthly period. With 10,000 gallons in storage at the beginning the summer season (April 13) and some additional rainwater (computations on precipitation to gallons of storage is below) it is hoped that I can accumulate the additional water needed to eliminate entirely the need for all Tier III water.
I list below monthly averages for high and low temperatures and precipitation.
Month Avg. Avg. Mean Avg. Record Record
High Low Precip. High Low
| Jan | 54°F | 42°F | 48°F | 6.95 in. | 82°F (1962) | 26°F (1949) |
| Feb | 59°F | 44°F | 52°F | 7.32 in. | 80°F (1964) | 26°F (1989) |
| Mar | 63°F | 45°F | 54°F | 4.59 in. | 88°F (1952) | 24°F (1977) |
| Apr | 67°F | 47°F | 57°F | 1.91 in. | 92°F (1996) | 29°F (1976) |
| May | 71°F | 50°F | 61°F | 0.89 in. | 100°F (1976) | 31°F (1976) |
| Jun | 76°F | 53°F | 65°F | 0.14 in. | 110°F (1961) | 40°F (1976) |
| Jul | 80°F | 55°F | 68°F | 0.00 in. | 109°F (1972) | 34°F (1975) |
| Aug | 80°F | 55°F | 68°F | 0.05 in. | 105°F (1998) | 41°F (1996) |
| Sep | 79°F | 54°F | 67°F | 0.21 in. | 109°F (1958) | 40°F (1985) |
| Oct | 73°F | 51°F | 62°F | 1.49 in. | 106°F (1980) | 34°F (1974) |
| Nov | 62°F | 46°F | 54°F | 4.31 in. | 88°F (1980) | 30°F (1974) |
| Dec | 54°F | 42°F | 48°F | 7.59 in. | 79°F (1967) | 20°F (1990) |
Total total annual Rainfall 35.35 in.
I am now tracking actual precipitation by week for 2014.
Jan 1 0.0
Jan 8 0.0
Jan 15 0.0
Jan 22 0.0
Jan 29 0.0
Feb 5 0.7
Feb 12 0.38
Feb 19 0.0
Feb 26 0.84
Mar 5 0.14
Mar 12 0.0
Mar 19 0.05
Mar 26 0.44
Apr 2
My measurement of precipitation to gallons of water harvested is estimated to be approximately 1,000 gallons for each inch of rain. Right now I am only harvesting the rain from about half my roof. Since my house footprint is 3,200 sq. ft. I estimate that 1,600 sq. ft. of footprint (half) is yielding the 1,000 gallons of water. To cross check this number, each foot of roof footprint is generating 7.48/12 = .623 gallons of water for each inch of rain, and .623 gallons x 1,600 sq. ft. = 1,000 gallons of water generated for an inch of rain.
The table below recapitulates the rainfall for the 6 summer months categorized into bimonthly pairs corresponding to the bimonthly billing periods.
Computation of Rainwater Collected Per Inch of Water for Summer Months
Period Estimated Potential Potential
Precipitation Rain Harvest Rain Harvest
(in inches) Half Roof Full Roof
(in gallons) (in gallons)
May - Jun 1.78 1,780 3,560
Jul - Aug .16 160 320
Sep - Oct .99 990 1,980
Totals 2.93 2,930 5,860
Even if I could capture every gallon of water generated during this period of time for the entire roof, with a storage capacity of 10,000 gallons I would only be capturing 10,000 gallons prior to April 12, and 5,860 gallons after April 13, for a total of 15,860 gallons. The Tier III demand is 20,000 gallons per bimonthly period for three periods, or 46,000 gallons. So, we have a deficit of 30,140 gallons. The only way to improve this situation is to increase the storage capacity so that by April 13, there is more water stored, or to reduce the demand by further conservation techniques.
On the bright side, the reduction to 30,140 gallons of Tier III water will save approximately $603.40 on the water bill, but only $317.48 is attributable to the water storage and the remainder to the pressure reduction.
The cost of 1,100 gallons of water storage is approximately $300, or $0.27 per gallon. 10,000 gallons will cost approximately $2,700. So, the anticipated return on investment (ROI) on $2,700 will be $317.48 per year less $130 for depreciation and maintenance, or $187.28 net, and a 6.9% (ROI) on an average year. I can only assume that the cost of water will continue to rise, while the cost for the storage system will be a sunk cost.
The ROI on the pressure reduction regulator is much higher, probably paying for itself in less than one year. I found one for under $100, but have not installed it yet.
last modified 10/16/2014
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