Correspondence among

Slight correction...most old pipe from the home to the shut-off is galvanized, and the majority of lead they have seen is from the shut-off to the main. Apologies for not getting this report written up, but I keep getting sidetracked with NDWAC LCR and RTCR primacy packages. I will try to get that written up and out to you in the next week. If I get copies of the latest results 1 will forward them, but my understanding is that the DEQ lab runs the samples, so they should be available within DEQ as well. Miguel A. Del Toral xxxEND_PAGE:deq16_b5_0892_4900_0976 Regulations Manager U.S. EPA RS GWDWB 77 West Jackson Blvd, (WG-15J) Chicago, IL 60604 Phone: (312) 886-5253

Hi, Steve. | found that interesting that the Walters’ interior piping is all PVC, and they have an iron pre-filter at the service connection. | remember in a discussion with Miguel, and maybe he can explain further, that systems with iron removal treatment had higher levels of lead at the tap, especially if the bacteria had been allowed to overgrow the filter. Seems there was a higher amount of lead particulate in the system. Miguel said in his email to us on 2/27 at 4:58am, that: “Fe/Mn can transport lead from the lead service lines into the home. The lead sorbs onto the Fe/Mn particles. In SW systems, the Fe typically is released from the water mains.” Perhaps the iron pre-filter is contributing to the high lead levels? Jennifer

Miguel and Jennifer, Thank you for this information, we will take it under consideration. The City of Flint: - Has a90™ percentile lead level of 6.0 ppb based on 100 samples collected in its most recent monitoring period of 7/1/2014 ~ 12/31/2014, with 2 samples (23 & 37 ppb) over the Al, - Hasago™ percentile copper level of(110 ppb based an 100 samples collectegin its most recent monitoring period of 7/1/2014 — 12/31/2014, with no Samples over the Cu AL - Has an Optimized Corrosion Control Program ~ Conducts quarterly Water Quality Parameter monitoring at 25 sites and has not had any unusual results. - Has never had a 90" percentile lead AL exceedance ~ Continues to meet all applicable plant tap standards and treatment technique requirements at its WTP Has developed and implemented an Operational Evaluation of its treatment and distribution systems, and continues to adjust and update this OE based on updated quarterly resuits My understanding from Ben Grumbles and the LCR Short Term Revisions is that “EPA regulations require water systems to develop a targeted sampling pool, focused on those sites with the greatest risk of lead leaching. All compliance samples used to determine the 90" percentile must come from that sampling pool.” [40 CFR 141.80(c)(1}], 56 Fed Reg. 26518 (June, 7, 1991}, [AOCFR 141.90(a} iv}, and 40 CFR 141.90(h}(2)). Our office continues to wark with our cammunity water systems to follow these and ail other requirements of the current lead and copper regulations. 212 Browning, the site in question, is not part of the City’s established sample site pool. The residence consists of PVC plumbing materials, and has an iron pre-filter at the service connection. Regarding TTHM, the most recent quarter monitoring from February 2015 was issued today by the jab. While 2 of the 8 DBP compliance sites continue to have an LRAA that exceeds the standard, quarterly results at all 8 DBP compliance sites were below less than half the standard level of 80 ppb, the highest being 28.5 ppb. Only one site now has an QEL over 80 ppb, at 85 ppb. Stephen Busch, P.E. Lansing and Jackson District Supervisor Office of Drinking Water and Municipal Assistance MDEQ 517-643-2314

Date: Friday, February 27, 2015 1:48:06 PM Miguel and Jennifer, Thank you for this information, we will take it under consideration. The City of Flint: - Has agoth percentile lead level of 6.0 ppb based on 100 samples collected in its most recent monitoring period of 7/1/2014 — 12/31/2014, with 2 samples (23 & 37 ppb) over the AL. - Hasagoth percentile copper level of 110 ppb based on 100 samples collected in its most recent monitoring period of 7/1/2014 — 12/31/2014, with no samples over the Cu AL. - Has an Optimized Corrosion Control Program - Conducts quarterly Water Quality Parameter monitoring at 25 sites and has not had any unusual results. - Has never hada 90" percentile lead AL exceedance - Continues to meet all applicable plant tap standards and treatment technique requirements at its WTP - Has developed and implemented an Operational Evaluation of its treatment and distribution systems, and continues to adjust and update this OE based on updated quarterly results My understanding from Ben Grumbles and the LCR Short Term Revisions is that “EPA regulations require water systems to develop a targeted sampling pool, focused on those sites with the greatest risk of lead leaching. All compliance samples used to determine the got percentile must come from that sampling pool.” [40 CFR 141.80(c)(1)], 56 Fed Reg. 26518 (June, 7, 1991), [40CFR 141.90(a)(1) (v), and 40 CFR 141.90(h)(2)]. Our office continues to work with our community water systems to follow these and all other requirements of the current lead and copper regulations. 212 Browning, the site in question, is not part of the City’s established sample site pool. The residence consists of PVC plumbing materials, and has an iron pre-filter at the service connection. Regarding TTHM, the most recent quarter monitoring from February 2015 was issued today by the lab. While 2 of the 8 DBP compliance sites continue to have an LRAA that exceeds the standard, quarterly results at all 8 DBP compliance sites were below less than half the standard level of 80 ppb, the highest being 28.5 ppb. Only one site now has an OEL over 80 ppb, at 85 ppb. Stephen Busch, P.E. Lansing and Jackson District Supervisor Office of Drinking Water and Municipal Assistance MDEQ 517-643-2314 xxxEND_PAGE:deq03_b475_2112_2118_1

Date: Friday, February 27, 2015 1:48:06 PM Miguel and Jennifer, Thank you for this information, we will take it under consideration. The City of Flint: - Has agoth percentile lead level of 6.0 ppb based on 100 samples collected in its most recent monitoring period of 7/1/2014 — 12/31/2014, with 2 samples (23 & 37 ppb) over the AL. - Hasagoth percentile copper level of 110 ppb based on 100 samples collected in its most recent monitoring period of 7/1/2014 — 12/31/2014, with no samples over the Cu AL. - Has an Optimized Corrosion Control Program - Conducts quarterly Water Quality Parameter monitoring at 25 sites and has not had any unusual results. - Has never hada 90" percentile lead AL exceedance - Continues to meet all applicable plant tap standards and treatment technique requirements at its WTP - Has developed and implemented an Operational Evaluation of its treatment and distribution systems, and continues to adjust and update this OE based on updated quarterly results My understanding from Ben Grumbles and the LCR Short Term Revisions is that “EPA regulations require water systems to develop a targeted sampling pool, focused on those sites with the greatest risk of lead leaching. All compliance samples used to determine the got percentile must come from that sampling pool.” [40 CFR 141.80(c)(1)], 56 Fed Reg. 26518 (June, 7, 1991), [40CFR 141.90(a)(1) (v), and 40 CFR 141.90(h)(2)]. Our office continues to work with our community water systems to follow these and all other requirements of the current lead and copper regulations. 212 Browning, the site in question, is not part of the City’s established sample site pool. The residence consists of PVC plumbing materials, and has an iron pre-filter at the service connection. Regarding TTHM, the most recent quarter monitoring from February 2015 was issued today by the lab. While 2 of the 8 DBP compliance sites continue to have an LRAA that exceeds the standard, quarterly results at all 8 DBP compliance sites were below less than half the standard level of 80 ppb, the highest being 28.5 ppb. Only one site now has an OEL over 80 ppb, at 85 ppb. Stephen Busch, P.E. Lansing and Jackson District Supervisor Office of Drinking Water and Municipal Assistance MDEQ 517-643-2314 xxxEND_PAGE:deq01_b343_4124_4130_1 004125

Miguel and Jennifer, Thank you for this inforraation, we will take it under consideration. The City of Flint: - Has a 90" percentile lead fevel of 6.0 ppb based on 100 samples collected in its most recent monitoring period of 7/1/2014 ~ 12/31/2044, with 2 samples (23 & 37 pnb} over the AL. - Has a 90" percentile comper level of 110 ppb based an 100 samples collected in its mast recent monitoring period of 7/1/2014 - 12/31/2014, with no samples over the Cu AL. - Has an Cptimized Corrosion Control Program - Conducts quarterly Water Quality Pararneter manttoring at 25 sites and has not had any unusual results. - as never had a 90" percentile lead AL exceedance - Continues to meet all applicable plant tap standards and treatment technique requirements at its WTP - Has developed and implemented an Operational Evaluation of its treatrnent and distributian systems, and continues to aciiust and update this OF based on updated quarterly results My understanding fram Ben Grurnbles and the LCR Short Terra Revisions is that "EPA regulations require water systerns to develop a targeted sarnnling pool, focused on thase sites with the greatest risk of lead leaching. All compliance samples used ta determina the go” percentile must come fram that sarnpling pool.” [40 CFR 144. 80(cH4}] 56 Fed Reg. 26518 (June, 7, 1999), I40CFR 141. 90fa ivi, and 40 CFR 147. 90(hH2}) Gur office continues to work with our coramunity water systems to follow these and all other requirements of the current lead and conper regulations. xxxEND_PAGE:deq18_b054_0982_0987_1 212 Browning, the site in question, is not part of the City’s established sarnple site pool, The residence consists of PVC nlurnbing materials, and has an fron pre-filter at the service commection. Regarding TTHM, the most recent quarter monitoring fram February 2015 was issued today by the lab. While 2 of the & DBP compliance sites continue to have an LRAA that exceeds the standard, quarterly results at all 8 DAP corpliance sites were below less than half the standard level of 80 poh, the highest being 28.5 ppb. Only one site now has an OEL over 80 ppb, at 85 ppb. Stephen Busch, PE. Lansing and Jackson District Supervisor Office of Drinking Water and Municinal Assistance MDEQ SLY-643-2314