Houston Water routinely tests drinking water for total chromium and the results have consistently remained within US EPA’s drinking water standards of 100 parts per billion (ppb). Houston Water tested for chromium-6 in 2013-2014 as part of the EPA’s Unregulated Contaminant Monitoring Rule. Additional testing continued from 2017-2019 at groundwater plants and distribution sample points where Chromium-6 was detected. Additional distribution sites were selected temporarily in 2019 to monitor system lines. This allowed for levels near customer homes to be compared to levels leaving their respective plants. Houston Water Southwest Area Chromium-6 Test Results (ppb) Location Bellaire Braes Jul 2013 Feb 2014 Jul 2017 Dec 2017 Water Plants Mar 2018 Dec 2018 Feb 2019 May 2019 Sep 2019 Dec 2019 1.7 1.9 0.22 1.6 0.26 1.1 0.73 0.37 0.33 0.37 1.3 Facility Out of Service 1.8 1.7 0.55 Facility Out of Service Bellaire Braes Well 1ii Facility Out of Service Brookfield 4.9 5.4 5.0 5.1 2.4 4.6 4.5 4.8 4.6 5.8 District 90-2 3.1 3.5 3.3 4.2 4.3 6.5 4.0 3.1 4.4 District 111-2 4.9 2.3 Facility Out of Service Facility Out of Service 2.6 5.2 5.3 5.8 5.5 6.7 2.2 6.7 District 123 5.1 6.7 5.8 5.5 2.5 5.9 6.0 Facility Out of Service District 184 3.2 2.0 2.2 2.3 3.0 2.0 0.06 1.3 0.03 0.05 Parkglen-1 2.6 2.5 2.8 2.5 2.3 3.8 4.1 3.3 0.06 2.1 Parkglen West 4.4 4.0 4.4 Facility Out of Service 4.0 4.1 4.0 Facility Out of Service Distribution Sample Points (DSP) Collected to Monitor Levels Observed in Water Lines Near Customer Homes DSP D-District 111- 2iii DSP 100v DSP Parkglen MUDiv DSP Brookfield -1vi DSP Brookfield -2 vi DSP D-123-1 vi DSP D-123-2vi DSP Parkglen West MUD-1vi 4.4 2.6 0.18 1.8 Not sampledi 4.9 Not 2.6 sampledi Not 2.8 2.3 0.78 2.4 1.7iv sampledi Site added temporary for two monitoring periods to observe levels in distribution in comparison to the plants. Site added temporary for two monitoring periods to observe levels in distribution in comparison to the plants. Site added temporary for two monitoring periods to observe levels in distribution in comparison to the plants. Site added temporary for two monitoring periods to observe levels in distribution in comparison to the plants. Site added temporary for two monitoring periods to observe levels in distribution in comparison to the plants. 2.9 1.5 1.4 2.9 5.3 1.0 0.42 6.6 1.8 0.40 0.47 0.59 3.5 0.28 2.6 2.5 0.69 0.79 -- -- 0.78 4.3 -- -- 1.2 1.7 -- -- 1.0 1.7 -- -- 0.95 1.2 -- -- i. PO Box 1562 Houston, Texas 77251-1562 HoustonPublicWorks.org Capital Projects Customer Account Services Houston Permitting Center Houston Water Transportation & Drainage Operations page 2 of 2 ii. Distribution samples were not collected in March 2018. Observations showed levels at distribution sites are either equal to or less than their associated source water plants. iii. Bellaire Braes Well 1 was sampled in March 2018, to observe levels in groundwater for this facility, whereas the other Bellaire Braes samples were from the plant storage tank where groundwater and surface water are mixed together. iv. D-D-111-2 is water from Bellaire Braes, District 111-2, and Brookfield Facilities v. Parkglen MUD is water from District 184, District 90-2, District 123, and Parkglen West Groundwater Facilities. In December 2018, Distribution Site Parkglen West MUD-2 was sampled instead of distribution site Parkglen MUD. vi. 100 represents Parkglen-1 Groundwater Facility. vii. Brookfield DSPs represent the Brookfield plant, D-123 DSPs represent the D-123 plants, the Parkglen West MUD-1 DSP represents the Parkglen West plant. The Safe Drinking Water Act (SDWA) requires EPA to determine the level of contaminants in drinking water at which no adverse health effects are likely to occur. EPA has not created a drinking water standard for chromium-6 by itself but does have a drinking water standard for total chromium, which includes chromium-6. In order to ensure that the greatest potential risk is addressed, EPA's regulation assumes that a measurement of total chromium is 100 percent chromium-6, the more toxic form of chromium. The highest reading of chromium-6 observed in the area around City Council District F is 6.7 ppb in 2014. More information regarding chromium in drinking water, including EPA’s responses to Frequently Asked Questions, can be found on EPA’s website: https://www.epa.gov/dwstandardsregulations/chromium-drinking-water PO Box 1562 Houston, Texas 77251-1562 HoustonPublicWorks.org