TABLE OF CONTENTS

4. DRINKING WATER INGESTION ........................................... 4-1

4.1 INTRODUCTION ............................................... 4-1

4.2 DRINKING WATER INGESTION STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

4.2.1 U.S. EPA, 2004 ........................................... 4-2

4.2.2. EPA Analysis of CSFII (USDA, 1998) . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

4.3 RECOMMENDATIONS .......................................... 4-4

4.4 REFERENCES FOR CHAPTER 4 .................................. 4-6
LIST OF TABLES

Table 4-1. Estimated Direct and Indirect Water Ingestion for Selected Age Categories Derived

from CSFII Data ....................................................... 4-7

Table 4-2. Estimated Direct and Indirect Community Water Ingestion By Source for Entire U.S.

Table 4-3. Estimated Direct and Indirect Water Ingestion, All Sources By Age Category for U.S.

Table 4-4. Estimated Direct and Indirect Community Water Ingestion By Age Category for U.S.

Table 4-5. Estimated Direct and Indirect Bottled Water Ingestion By Age Category for U.S.

Table 4-6 Estimated Direct and Indirect Other Water Ingestion By Age Category for U.S.

Population (All Ages) a .................................................. 4-8

Children ............................................................. 4-9

Children ............................................................ 4-10

Children ............................................................ 4-11

Children ............................................................ 4-12

Table 4-7. Summary of Recommended Community Drinking Water Ingestion Rates . . . . . 4-13

Table 4-8. Confidence in Water Ingestion Recommendations . . . . . . . . . . . . . . . . . . . . . . . . 4-14
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4. DRINKING WATER INGESTION 

4.1 INTRODUCTION 

Drinking water is a potential source of human exposure to toxic substances among 

children. Contamination of drinking water may occur at the water supply source (ground water 

or surface water); during treatment ( for example toxic by-products may be formed during 

chlorination); or post-treatment (such as leaching of lead or other materials from plumbing 

systems). Estimating the magnitude of the potential dose of toxics from drinking water requires 

information on the quantity of water consumed. The purpose of this section is to describe key 

published studies that provide information on drinking water ingestion among children (Section 

4.2) and to provide recommendations of ingestion rate values that should be used in exposure 

assessments (Section 4.3). 

Currently, the U.S. EPA uses the quantity 1 L per day for infants (individuals of 10 kg 

body mass or less) and children as a default drinking water ingestion rate (U.S. EPA, 1980; 

1991). This rate includes drinking water consumed in the form of juices reconstituted in the 

home and other beverages containing tapwater. The National Academy of Sciences (NAS, 1977) 

estimated that daily consumption of water may vary with levels of physical activity and 

fluctuations in temperature and humidity. It is reasonable to assume that children engaging in 

physically-demanding activities or living in warmer regions may have higher levels of water 

ingestion. 

Two studies cited in this chapter (US EPA, 2004 and EPA Analysis of CSFII) have 

generated data on drinking water ingestion rates. In general, these sources support EPA's use of 

1 L/day as an upper-percentile tapwater ingestion rate for children under 10 years of age. The 

respondents recorded the source and type of water ingested at home and away from home. The 

respondents had several choices for the source of water ingested at home. These included 

community water supply, household well or rain cistern, household or public spring, bottled 

water and other. Similarly, the respondents had several choices for the source of water ingested 

away from home. The choices included tap/fountain, bottled, other, don’t know, and not 

ascertain. Values associated with “don’t know” and “not ascertain” were referred to as “missing” 

in Table 4-2. U.S. EPA 2004 and the subsequent analysis by EPA of the CSFII data classified 

water ingestion rates as direct and indirect. Direct ingestion is defined as direct consumption of 

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plain water as a beverage at home and away from home from all sources including tap/fountain 

water from community water supply, household well or rain cistern, household or public spring, 

and bottled. It does not include water used for preparing beverages such as coffee or tea. 

Indirect ingestion includes water added during food preparation, but not water intrinsic to 

purchased foods. Indirect water includes for example, water used to prepare baby formulas, cake 

mix, and concentrated orange juice. In addition to presenting data on direct and indirect water 

ingestion, data for consumption of water from various sources (i.e., the community water supply, 

bottled water, and other sources) are also presented. For the purposes of exposure assessments 

involving site-specific contaminated drinking water, ingestion rates based on the community 

supply are most appropriate. Given the assumption that bottled water, and other purchased foods 

and beverages are widely distributed and less likely to contain source-specific water, the use of 

total water ingestion rates may overestimate the potential exposure to toxic substances present 

only in local water supplies; therefore, tapwater ingestion of community water, rather than total 

water ingestion, is emphasized in this section. 

The studies on drinking water ingestion that are currently available are based on shortterm survey data (two days). Although short-term data may be suitable for obtaining mean or 

median ingestion values that are representative of both short- and long-term ingestion 

distributions , upper and lower -percentile values may be different for short-term and long-term 

data. It should also be noted that most drinking water surveys currently available are based on 

recall. This may be a source of uncertainty in the estimated ingestion rates because of the 

subjective nature of this type of survey technique. 

 The actual percentile distributions for water ingestion are presented in this handbook, 

where sufficient data are available. To facilitate comparisons between studies, the mean and the 

90th percentiles are given for all studies. 

Other drinking water studies based on older data were presented in the Exposure Factors 

Handbook (U.S. EPA, 1997a). 

4.2 DRINKING WATER INGESTION STUDIES 

4.2.1 U.S. EPA, 2004 

The U.S. EPA analyzed the combined 1994-96 and 1998 Continuing Survey of Food 

Intake by Individuals (CSFII) data sets to examine the ingestion of water by various segments of 

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the U.S. population. The CSFII is a continuing survey of food consumption habits in the U.S. In 

the initial 1994-96 survey, over 15,000 respondents provided data on what they ate and drank 

over two non-consecutive days; a 1998 supplement using the same methodology added several 

thousand children to the database. The 1994-96 survey and 1998 supplement are referred to 

collectively as CSFII 1994-96, 1998. Each individual in the survey was assigned a sample weight 

based on his or her demographic data; these weights were taken into account when calculating 

mean and percentile water ingestion from various sources. The U.S. EPA used the drinking water 

ingestion data in the CSFII 1994-96, 1998 to derive estimates of consumption rates by age 

groups. The ingestion rates are expressed in both milliliters per day (mL/day) and milliliters per 

th th kilogram body weight per day (mL/kg/day). Table 4-1 presents the estimated mean, 90 , and 95

percentile ingestion of water, including both direct and indirect sources. 

The principal advantages of this study are (1) that the survey was designed to obtain a 

statistically valid sample of the entire United States population that included children and low 

income groups ; (2) sample weights were provided that facilitated proper analysis of the data and 

accounted for non-response; and (3) that the sample size (more than 20,000 persons) is sufficient 

to allow categorization within narrowly defined age categories. However, the design of the 

survey has some weaknesses, including the practice of surveying each participant on only two 

days; this reduces the precision of the measurement for each individual and may tend to 

exaggerate the effects of persons on both extremes of the distribution of ingestion, although the 

degree to which this may happen is unknown. Also, the design of the study, while being welltailored for the overall population of the United States and conducted throughout the year to 

account for seasonal variation, is of limited utility for assessing small and potentially at-risk 

subpopulations based on ethnicity, medical status, geography, or other factors such as activity 

level. 

4.2.2. EPA Analysis of CSFII (USDA, 1998) 

The water ingestion study described in the previous section yielded useful results for 

direct and indirect water ingestion (Table 4-1). However, the age categories used by the 

investigators were not compatible with the standardized age categories used in this Handbook. 

Water ingestion for the target age groups of this Handbook were derived from the CSFII. 

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In the analysis of the CSFII 1994-96, 1998, data (US EPA, 2004) total water ingestion 

was defined as consisting of community water supply, bottled water, other sources, and missing 

sources. Missing sources represent water sources that the survey respondent was unable to 

identify. In addition to these sources, the data also distinguish between direct and indirect water 

consumption. Direct consumption is water consumed directly from the tap while indirect 

consumption is water added during final food or beverage preparation in the home or food 

establishment (e.g., restaurants, school cafeterias). In this Handbook, indirect and direct water 

use were not distinguished. Table 4-2 provides the estimates for the mean direct and indirect 

water consumption, broken down by water source, for the entire U.S. population, including both 

children and adults. Also included are estimates of the 90th percentile and the 95th percentile 

ingestion rates. Tables 4-3 through 4-6 show mean and percentile consumption, expressed as 

mL/day and ml/kg/day, of all water, community water, bottled water, and other water, 

respectively, for each of the target age categories. 

The data show that the quantity of water ingested per unit mass of body weight is at a 

maximum in the first month of life and decreases with increasing age (Table 4-3). The 

significance of this finding is that the younger, vulnerable ages (i.e., infants) have higher dose 

rates per unit of body weight. The pattern of higher dose rate per unit of body weight is similar 

for individual sources of water (e.g., community water, bottled water, and other water (Tables, 4­

4, 4-5, and 4-6.) 

The CSFII 1994-96, 1998 data have both strengths and limitations with regard to 

estimating water ingestion. These are discussed in some detail in Chapter 8 of US EPA (2004). 

The strengths lie in the design of the survey in that it was constructed to collect a statistically 

representative sample of the U.S. population (i.e., obtain data from a sufficiently large and varied 

sample set) and the survey was specific in detailing types and composition with respect to water 

of food and drink. The large size of the sample population (> 20,000) total and over sampling of 

children enhances the precision and accuracy of the estimates for the overall population and child 

population subsets. Data were collected for only 2days and does not necessarily represent “usual 

intake.” “Usual dietary intake” refers to the long-run average of daily intakes by an individual. 

Thus, upper percentile estimates may differ between short term and long-term data because shortterm food consumption data tend to be inherently more variable. However, that variability due to 

short term duration of the survey does not result in bias of estimates of overall mean 

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consumption levels (U.S. 2004). In addition, the survey was conducted on non-consecutive days, 

which improves the variance over consecutive days of consumption. The survey was 

administered such that an interviewer went through the data collection process for the initial day 

to show the participants the proper response methodology. The second day of the survey was 

reported by the participant. The two non-consecutive days of data collection, although an 

advantage over two consecutive days, provides limited information on individual respondents. 

The two-day mean for an individual can easily be skewed for numerous reasons. Estimation at 

the individual respondent level was not, however, an objective of the survey. The large sample 

does provide useful information on the overall distribution of ingestion by the population and 

should reflect adequately the range among respondent variability. Another limitation of these 

data is that the survey design does not support generating water consumption estimates for 

certain populations of interest, including Native Americans with traditional lifestyles, people who 

may consume large amounts live in hot climates, people who consume large amounts of water 

because of physical activity, and people with medical conditions necessitating increased water 

intake. While these individuals were participants in the survey, they are not present in sufficient 

numbers to support separate water ingestion estimates. 

4.3 RECOMMENDATIONS 

The studies described in this section were used in selecting recommended drinking water 

ingestion rates for children. A summary of the recommended values for drinking water ingestion 

rates is presented in Table 4-7. The ingestion rates, as expressed as mL/kg/day, generally 

decrease with age. 

A characterization of the overall confidence in the accuracy and appropriateness of the 

recommendations for drinking water is presented in Table 4-8. The Exposure Factors Handbook 

(U.S. EPA, 1997a) gave this factor a medium confidence rating. However, the confidence score 

of the overall recommendations has been increased to high for this report because of the addition 

of newer data from the CSFII 1994-96, 1998. 

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4.4 REFERENCES FOR CHAPTER 4 

National Academy of Sciences (NAS). (1977) Drinking water and health. Vol. 1. Washington, DC: National 

Academy of Sciences-National Research Council. 

USDA. (1998) Continuing survey of food intakes by individuals: 1994-96, 1998. U.S. Department of Agriculture, 

Agricultural Research Service. 

U.S. EPA. (1980) U.S. Environmental Protection Agency. Water quality criteria documents; availability. Federal 

Register, (November 28) 45(231):79318-79379. 

U.S. EPA. (1991) National primary drinking water regulations; final rule. Federal Register. 56(20):3526-3597. 

January 30, 1991. 

U.S. EPA. (1997a) Exposure Factors Handbook. Washington, DC: Office of Research and Development, 

(EPA/600/P-95/002F). 

U.S. EPA. (2004) Estimated Per Capita Water Ingestion and Body Weight in the United States— an Update: Based 

on Data Collected by the United States Department of Agriculture’s 1994-96 and 1998 Continuing Survey of 

Food Intakes by Individuals. EPA Office of Water. EPA-822-R-00-001. October 2004. 

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Table 4-1. Estimated Direct and Indirect Water Ingestion for Selected Age Categories Derived from CSFII Data 

Age Category 

less than 6 months 

Sample 

Size 

(N) 

772 

mL/day 

448 

Mean 

mL/kg/day 

77 

mL/day 

957 

90th 

Percentile Ingestion 

mL/kg/day mL/day 

174 1154 

95th 

mL/kg/day 

216 

6 months to <1 year 714 530 59 1029 118 1278 148 

birth to <2 years 2526 420 49 900 117 1079 150 

1 to <4 years 3855 424 31 823 60 1029 75 

4 to <7 years 3202 545 27 1053 53 1303 68 

birth to <6 years 7973 470 36 937 76 1132 104 

7 to <11 years 1100 607 20 1129 36 1418 45 

11 to <15 years 816 811 16 1622 32 1961 40 

15 to <20 years 825 991 15 1894 29 2385 38 

20 years and older 9323 1460 20 2549 35 3194 44 

Source: U.S. EPA, 2004 

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Table 4-2. Estimated Direct and Indirect Community Water Ingestion By Source for Entire U.S. Population (All Ages)a 

Water Source Sample Size 

Mean b 90 Percentile th b 95 Percentile th b 

mL/day mL/kg/day mL/day mL/kg/day mL/day mL/kg/day 

Community Water Supply 20,607 927 15 2,016 32 2,545 42 

Bottled Water 20,607 163 3 473 11 911 22 

Other Sources 20,607 128 2 296 7 947 18 

Missing Sources c 20,607 16 0.3 0 0 0 0 

All Sources 20,607 1,233 20 2,141 48 2,707 65 

a

Estimates are based on 2-day averages for non-consecutive days. b “All Sources” may not be exactly the sum of the other sources in the table due to weighting factors applied to each individual in the survey. c Missing sources are those sources of water that the survey respondent was unable to identify. 

Source: U.S. EPA Analysis of CSFII 1994-96, 1998 

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Table 4-3. Estimated Direct and Indirect Water Ingestion, All Sources By Age Category for U.S. Children 

Age (years) Sample 

Size 

Quantity, Percentiles (ml/person-day) 

Mean Min 1st 2nd 5th 10th 25th 50th 75th 90th 95th 98th 99th Max 

birth to <1 month 91 301 0 0 0 0 0 0 163 544 855 974 1076 1541 1541 

1 to <3 months 253 368 0 0 0 0 0 0 268 696 891 1022 1177 1276 1941 

3 to <6 months 428 528 0 0 0 0 0 89 550 812 1026 1303 1458 1516 2686 

6 to <12 months 714 530 0 0 0 0 37 182 506 771 1032 1282 1523 1695 2034 

1 to <2 years 1040 358 0 0 0 30 68 148 286 479 735 985 1188 1281 2008 

2 to <3 years 1056 437 0 11 20 53 104 211 372 588 828 1008 1334 1681 2884 

3 to <6 years 4391 514 0 4 22 67 126 251 439 682 980 1206 1535 1798 4081 

6 to <11 years 1670 600 0 8 35 111 170 305 503 802 1132 1409 1704 2171 4281 

11 to <16 years 1005 835 0 12 65 140 225 401 667 1100 1649 1962 2561 3194 6105 

16 to <21 years 752 1027 0 0 6 104 207 403 770 1341 2014 2599 3860 4943 13358 

Quantity, Percentiles (ml/kg-day) 

birth to <1 month 91 88 0 0 0 0 0 0 19 171 236 269 332 485 485 

1 to <3 months 253 75 0 0 0 0 0 0 42 134 172 247 298 375 534 

3 to <6 months 428 72 0 0 0 0 0 7 70 117 149 187 214 224 288 

6 to <12 months 714 56 0 0 0 0 0 15 50 84 117 145 171 195 254 

1 to <2 years 1040 30 0 0 0 0 4 12 24 39 62 84 105 121 201 

2 to <3 years 1056 30 0 0 0 0 4 13 25 40 59 72 94 129 173 

3 to <6 years 4391 27 0 0 0 0 3 12 23 37 54 68 85 101 213 

6 to <11 years 1670 20 0 0 0 0 3 9 17 26 38 48 63 75 110 

11 to <16 years 1005 16 0 0 0 2 4 7 13 20 31 39 52 61 96 

16 to <21 years 752 15 0 0 0 1 3 6 12 20 32 43 75 0 161 

Source of Data: USDA Continuing Survey of Food Intakes by Individuals (CSFII), 1994-96, 1998 

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Table 4-4. Estimated Direct and Indirect Community Water Ingestion By Age Category for U.S. Children 

Age (years) Sample 

Size 

Quantity, Percentiles (ml/person-day) 

Mean a Min 1st 2nd 5th 10th 25th 50th 75th 90th 95th 98th 99th Max 

birth to <1 month 91 297 0 0 0 0 0 0 0 353 709 856 859 957 957 

1 to <3 months 253 359 0 0 0 0 0 0 0 459 815 918 1124 1177 1525 

3 to <6 months 428 464 0 0 0 0 0 0 148 696 930 1056 1351 1443 2104 

6 to <12 months 714 436 0 0 0 0 0 17 220 628 886 1056 1385 1523 2034 

1 to <2 years 1040 303 0 0 0 0 0 60 188 404 632 842 1076 1216 2008 

2 to <3 years 1056 351 0 0 0 0 0 79 246 480 684 879 1075 1393 2884 

3 to <6 years 4391 409 0 0 0 0 4 98 291 548 834 1078 1387 1682 2963 

6 to <11 years 1670 475 0 0 0 0 22 133 352 649 980 1237 1557 1974 2691 

11 to <16 years 1005 656 0 0 0 0 31 182 473 829 1344 1619 2104 2589 6105 

16 to <21 years 752 819 0 0 0 0 21 219 591 1049 1716 2299 3397 3883 13358 

Quantity, Percentiles (ml/kg-day) 

birth to <1 month 91 86 0 0 0 0 0 0 0 101 198 234 269 269 269 

1 to <3 months 253 74 0 0 0 0 0 0 0 86 150 205 289 316 375 

3 to <6 months 428 67 0 0 0 0 0 0 12 95 134 159 203 216 288 

6 to <12 months 714 49 0 0 0 0 0 0 19 68 101 125 170 185 254 

1 to <2 years 1040 26 0 0 0 0 0 4 16 34 52 70 96 107 177 

2 to <3 years 1056 25 0 0 0 0 0 4 16 32 48 59 82 111 162 

3 to <6 years 4391 24 0 0 0 0 0 4 15 30 46 60 79 93 213 

6 to <11 years 1670 18 0 0 0 0 0 4 11 21 33 43 58 71 110 

11 to <16 years 1005 13 0 0 0 0 0 3 9 16 25 33 42 54 96 

16 to <21 years 752 12 0 0 0 0 0 3 9 16 25 33 45 63 161 

Source of Data: USDA Continuing Survey of Food Intakes by Individuals (CSFII), 1994-96, 1998 a

 The mean values are for consumers only; while the percentiles referred to the whole population. 

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Table 4-5. Estimated Direct and Indirect Bottled Water Ingestion By Age Category for U.S. Children 

Age (years) Sample 

Size 

Quantity, Percentiles (ml/person-day) 

Mean a Min 1st 2nd 5th 10th 25th 50t0h 75th 90th 95th 98th 99th Max 

birth to <1 month 91 278 0 0 0 0 0 0 0 30 460 576 993 1541 1541 

1 to <3 months 253 331 0 0 0 0 0 0 0 0 579 790 896 1070 1941 

3 to <6 months 428 415 0 0 0 0 0 0 0 0 585 774 1164 1458 1516 

6 to <12 months 714 355 0 0 0 0 0 0 0 59 506 762 1051 1338 1736 

1 to <2 years 1040 246 0 0 0 0 0 0 0 0 216 355 635 810 1834 

2 to <3 years 1056 319 0 0 0 0 0 0 0 0 281 495 750 1006 2737 

3 to <6 years 4391 361 0 0 0 0 0 0 0 0 325 532 828 1045 2917 

6 to <11 years 1670 425 0 0 0 0 0 0 0 0 340 532 850 1079 3808 

11 to <16 years 1005 542 0 0 0 0 0 0 0 0 384 710 1183 1431 3135 

16 to <21 years 752 650 0 0 0 0 0 0 0 0 473 946 1710 2366 4880 

Quantity, Percentiles (ml/kg-day) 

birth to <1 month 91 85 0 0 0 0 0 0 0 9 134 268 317 485 485 

1 to <3 months 253 66 0 0 0 0 0 0 0 0 95 164 175 295 534 

3 to <6 months 428 59 0 0 0 0 0 0 0 0 74 114 150 197 220 

6 to <12 months 714 38 0 0 0 0 0 0 0 2 50 86 112 140 225 

1 to <2 years 1040 21 0 0 0 0 0 0 0 0 18 28 55 67 184 

2 to <3 years 1056 23 0 0 0 0 0 0 0 0 17 36 55 83 140 

3 to <6 years 4391 21 0 0 0 0 0 0 0 0 17 29 45 58 147 

6 to <11 years 1670 15 0 0 0 0 0 0 0 0 9 17 28 38 94 

11 to <16 years 1005 10 0 0 0 0 0 0 0 0 6 13 22 33 54 

16 to <21 years 752 10 0 0 0 0 0 0 0 0 7 14 27 30 63 

Source of Data: USDA Continuing Survey of Food Intakes by Individuals (CSFII), 1994-96, 1998 a

 The mean values are for consumers only; while the percentiles referred to the whole population. 

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Table 4-6 Estimated Direct and Indirect Other Water Ingestion By Age Category for U.S. Children 

Age (years) 

Sample 

Size 

Quantity, Percentiles (ml/person-day) 

Mean a Min 1st 2nd 5th 10th 25th 50th 75th 90th 95th 98th 99th Max 

birth to <1 month 91 166 0 0 0 0 0 0 0 0 0 0 353 422 550 

1 to <3 months 253 276 0 0 0 0 0 0 0 0 0 397 560 691 1183 

3 to <6 months 428 431 0 0 0 0 0 0 0 0 0 386 740 941 2597 

6 to <12 months 714 342 0 0 0 0 0 0 0 0 32 411 720 963 1478 

1 to <2 years 1040 253 0 0 0 0 0 0 0 0 0 118 412 482 1495 

2 to <3 years 1056 342 0 0 0 0 0 0 0 0 54 347 587 739 1652 

3 to <6 years 4391 396 0 0 0 0 0 0 0 0 59 345 660 831 4052 

6 to <11 years 1670 440 0 0 0 0 0 0 0 0 181 470 843 1049 2015 

11 to <16 years 1005 640 0 0 0 0 0 0 0 0 346 794 1183 1726 3244 

16 to <21 years 752 598 0 0 0 0 0 0 0 0 118 446 857 1658 2729 

Quantity, Percentiles (ml/kg-day) 

birth to <1 month 91 49 0 0 0 0 0 0 0 0 0 0 130 130 173 

1 to <3 months 253 55 0 0 0 0 0 0 0 0 0 55 110 149 237 

3 to <6 months 428 64 0 0 0 0 0 0 0 0 0 53 106 170 260 

6 to <12 months 714 37 0 0 0 0 0 0 0 0 1 34 79 95 171 

1 to <2 years 1040 22 0 0 0 0 0 0 0 0 0 10 30 45 150 

2 to <3 years 1056 26 0 0 0 0 0 0 0 0 3 22 39 60 173 

3 to <6 years 4391 22 0 0 0 0 0 0 0 0 1 17 35 47 133 

6 to <11 years 1670 16 0 0 0 0 0 0 0 0 5 15 29 36 73 

11 to <16 years 1005 12 0 0 0 0 0 0 0 0 6 14 25 35 65 

16 to <21 years 752 9 0 0 0 0 0 0 0 0 1 7 14 27 46 

Source of Data: USDA Continuing Survey of Food Intakes by Individuals (CSFII), 1994-96, 1998 a

 The mean values are for consumers only; while the percentiles referred to the whole population. 

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Table 4-7. Summary of Recommended Community Drinking Water Ingestion Rates a 

Mean Percentilesb 

Age Category Reference 

50th 90th 95th 

mL/day mL/kg-day mL/day mL/kg-day mL/day mL/kg-day mL/day mL/kg-day 

birth to <1 month 297 86 0 0 709 198 856 234 Table 4-4

1 to <3 months 359 74 0 0 815 150 918 205 Table 4-4

3 to <6 months 464 67 148 12 930 134 1056 159 Table 4-4

6 to <12 months 436 49 220 19 886 101 1056 125 Table 4-4

1 to <2 years 303 46 188 16 632 52 842 70 Table 4-4

2 to <3 years 351 25 246 16 684 48 879 59 Table 4-4

3 to <6 years 409 24 291 15 834 46 1078 60 Table 4-4

6 to <11 years 475 18 352 11 980 33 1237 43 Table 4-4

11 to <16 years 656 13 473 9 1344 25 1619 33 Table 4-4

16 to <21 years 819 12 591 9 1716 25 2299 33 Table 4-4

a Community water includes both direct and indirect water consumption (e.g., plain water, water used to prepare foods and beverages) b

 Lower percentiles are shown in Table 4-4. 

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Table 4-8. Confidence in Water Ingestion Recommendations 

Considerations Rationale Rating 

Study Elements 

• Level of peer review The CSFII 1994-96, 1998 had thorough SAB expert panel review. , 

The EPA analysis of the CSFII data used to estimate the 

recommended values in this Handbook used the same methodology 

as was reviewed and approved by the SAB, but the particular values 

have not been peer reviewed. 

Medium 

• Accessibility The source data are available from the sponsoring agency. High 

• Reproducibility Methods are well-described. High 

• Focus on factor of interest The studies are directly relevant to tapwater, and data of similar 

quality were provided for other water sources 

High 

• Data pertinent to U.S. See “representativeness” below. NA 

• Primary data The CSFII 1994-96, 1998 contains primary data on recall of 

ingestion. 

High 

• Currency Data were collected between 1994 and 1998. Medium 

• Adequacy of data collection 

period 

These are two-day average ingestion data. However, long term 

variability may be small. Their use as a chronic ingestion measure 

can be assumed. 

Medium 

• Validity of approach The approach was competently executed. High 

• Study size The CSFII 1994-96, 1998 had sufficient sample populations (i.e., 

11,000) for the study. 

High 

• Representativeness of the

 population 

The CSFII 1994-96, 1998 was validated as demographically 

representative of the U.S. population, but may not be representative 

of specific segments of the population that may be of interest. 

Medium 

• Characterization of

 variability 

The full distributions were given in the main study. High 

• Lack of bias in study design

 (high rating is desirable) 

Bias was not apparent. High 

• Measurement error No physical measurements were taken. The method relied on recent 

recall of standardized volumes of drinking water containers, and 

was not validated. 

Medium 

Other Elements 

• Number of studies There was one key study for the recommendations. High 

• Agreement between

 researchers 

N/A Low 

Overall Rating The data are excellent and acceptably current. However, may not 

be representative of specific segments of the population. 

High 

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