**Anemia testing** : If the caregiver provided informed consent, trained field staff cleaned a fingertip with disinfection liquid, and then collected a finger prick blood sample using a spring loaded, disposable lancet from children in study households between the ages of 6 and 60 months. A drop of blood was placed in a micro-cuvette, and the hemoglobin concentration was measured (HemoCue, HemoCue Ltd, Angelholm, Sweden) and reported to the caregiver. We classified children as severely anemic if their hemoglobin concentration was < 7.0 grams per deciliter (g/dl), moderately anemic if their hemoglobin concentration is 7.0 - 9.9 g/dl, and mildly anemic if their hemoglobin concentration is 10.0 - 11.9 g/dl [32]. Parents of children who were severely anemic were advised to visit the nearest health facility for medical attention.

**Water Sample Collection and Analysis:** Field staff collected 100 ml water samples from a random sample of approximately 400 households in each group to collect water samples from stored drinking water and from the household’s designated water source. At the time of sample collection, field staff recorded information about the water source, storage and treatment (if any). Water samples were stored and transported in ice boxes for analysis within 24 hours to a field lab and tested for _E. coli_ using membrane filtration within 36 hours of collection.  The lower and upper limits of detection were 1 and 200 colony forming units (CFU) per 100 ml.  Samples below the lower limited of detection were imputed at 0.5 (1/2 the limit of detection [33]), and samples beyond the upper limit of detection were imputed at the limit of detection (200).

**Child Stool Collection and Analysis:** At follow-up field staff collected stool from a random sample of 1,150 households (from an eligible list with replacement sampling) and collected stool from the youngest child over 21 months of age (<24 months at baseline). The field team left a user-friendly stool collection kit (sterilized spatula, paper, container) with the child’s mother with verbal and written instructions on how to collect the samples. They advised mothers to note the consistency, color, and presence of blood in stool.  The field staff then returned the following day to collect the stool samples.  At the time of collection, field staff observed the sample for consistency and presence of blood, and added 10% formalin preservative. The preserved samples were stored in a shaded, cool and dry place and transported to the National Institute for Cholera and Enteric Diseases (NICED, Kolkata).  NICED tested the samples within 30 days of collection for soil transmitted helminths ( _Ascaris lumbricoides, Trichuris trichuria, Ancylostoma duodenale_ and _Necator americanus_ ) and tapeworm helminths ( _Hymenolepis nana, Taenia sp., Diphyllobothrium latum_ ) using the Kato-Katz technique [34].  A separate aliquot was analyzed to determine the presence of protozoans ( _Giardia lamblia, Cryptosporidium sp., Entamoeba histolytica_ ) using a commercially available Enzyme-Linked Immunosorbent Assay (ELISA) kit (TechLab) [35,36]. If a child tested positive for one of the protozoan infections using ELISA, the result was confirmed using isolated DNA from the ELISA positive samples and PCR-restriction fragment length polymorphism (RFLP) methods for genotyping local isolates of _Giardia_ ( _β_ - giardin) [37], _Cryptosporidium_ (18s rRNA) [38], and _E. histolytica_ (SSU rRNA) [39].

**Community Questionnaire:** The community questionnaire was administered at the villagelevel.  We conducted surveys of the _Gram Panchayat_ secretary (main administrative official),

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