assess and m anage risk in drinking w a te r system s. A W ater Safety P lan (W SP) aim s to identify hazards to drinking w ater quality th at can be introduced at m ultiple points from the source to the tap. T he W S P does not, how ever, traditionally provide fo r identifying hazards th a t could com prom ise drinking w ater quality after it reaches the household tap, such as contam ination associated w ith w ater collection, storage, and treatm en t practices w ithin the hom e. T he aim o f th is m anual is to provide guidance on conducting a household survey as part o f a W ater Safety P lan fo r organized piped w ater supply system s in resource-lim ited settings.
S pecific exam ples intended to guide the planner in designing the survey are provided in the appendices. A sum m ary checklist for survey planning and com pletion is provided as A ppendix A.
B e f o r e Y o u S t a r t Successful im plem entation o f a household survey for a W ater Safety P lan requires good background know ledge o f the w a te r delivery system , the survey area, and the p o pulation in the service area. B efore initiating a survey, it w ill be helpful to gather the inform ation b elo w to help guide questionnaire developm ent and provide supporting inform ation to the report. Som e o f this data, particularly the data relating to w ater quality, m ay already be collected as part o f the W ater Safety P lan system description (W S P M o dule 2). O ther inform ation m ay be obtained from health departm ent or surveillance personnel, laboratory personnel, or com m unity health w orkers.

# P o p u l a t i o n d a ta
 D etailed m aps by com m unity or district (som e dividable cluster or area w ith defined boundaries and know n population size)  M o st recen t census data (for population estim ates, preferably by cluster)  A lternative w ater sources u sed (private w ells, rivers, springs, b ottled w ater, rain w ater, etc.), and the uses o f alternative sources (e.g., for drinking vs. other H e a lth d e p a r t m e n t  H o w m any hospitals and clinics (public and private) serve the area?
 Is there a surveillance system in place?
 Is there a regional or national estim ate for diarrhea incidence or gastrointestinal (G I) disease?  H ave there been any outbreaks or seasonal trends? (especially G I-related)
 Is there a know n, suspected, o r perceived health problem associated w ith the w ater (this m ay be anecdotal)? T im e m ust also be allotted fo r data cleaning, analysis, and report w riting, w hich could take several w eeks, and fo r presenting and review ing the data w ith the W S P team . B ecause the inform ation from the household survey contributes to Step 2 o f the W SP, it should be initiated early in the process, preferably concurrently w ith other System A ssessm ent activities.
B u d g e t P l a n n i n g B elo w are som e guidelines for estim ating th e household survey budget and som e tip s for handling paym ents. A ppendix B provides an exam ple o f calculating survey costs.

# I n t e r v i e w p e r s o n n e l
Interview ers m ay be paid on a daily basis or per questionnaire. I f paym ent is m ade on a per questionnaire basis, a sm all daily base rate should be paid, as w ell as a sm all rate fo r household visits w here the interview w as n o t com pleted, either because o f the o ccu p an ts' not being hom e or th eir refusal to participate. This practice w ill im prove adherence to household v isitation protocol. Interview ers should be paid a daily rate equivalent to the rate earned on an average fieldw ork day for training days.

# F i e l d m a n a g e r
T he field m anager should be paid at a daily rate slightly higher than the average daily rate o f the interview ers.

# T r a n s p o r t a t i o n
D rivers should be paid a daily rate for a full-tim e com m itm ent during field w o rk days.
A driver should include the cost o f gas and phone calls in the quoted rate.

# P h o t o c o p y i n g c o s t s

# P h o n e c a r d s o r c r e d i t
It is advisable to supply interview ers and the field co ordinator w ith phone cards or som e other form o f credit to encourage com m unication regarding protocol issues or security concerns w ith the field or study coordinator. To avoid overuse, consider either using a daily call log or supplying credit on a daily basis or every 2 days.

# W a t e r q u a l i t y t e s t i n g
C osts include on-site test kits and th e associated reagents test for chlorine or other desired param eters (e.g. turbidity, pH ). I f m icrobiology testing is done, include the cost o f processing or providing additional supplies to a local laboratory, or obtaining field test kits, such as D el A gua. C ollection bottles, labels, and a cooler w ill also be needed.

# D a ta e n t r y
D ata entry should be paid on a daily or per-questionnaire basis. Q uality should be spotchecked frequently to ensure careful data entry. I f sufficient personnel and financial resources are available, double data entry should be done, w here data is entered tw ice and th e com pleted databases are th en com pared to identify and correct errors in data entry.

# O t h e r c o s t s
A dditional item s m ay be needed, such as clipboards or binders fo r interview ers to use in th e field (consider closable plastic binders fo r w et clim ates), stationary supplies for posting training m aterials, pens and pencils, identification badges, etc. O nce an appropriate sam ple size has been determ ined, an additional ten percent o f h ouseholds should b e added to th e sam ple size to allow fo r refusals, unusable data, or other lim itations. I f the non-response rate is expected to be h igher than usual, then this percentage should be increased.
In som e cases it m ay be o f interest to obtain inform ation about specific areas or sub populations; exam ples are people not connected to the distribution netw ork, those w ho live farthest along th e distribution line, people in areas in close proxim ity to a know n source o f contam inants, those living in areas w ith frequent w ater outages, etc. I f such data are desired, selected households should be additional to and not included in th e calculated survey size. It is im portant to recognize th at th e sam ple size w ill not be sufficient to allow identification o f significant differences betw een populations (unless the survey is designed to do so from th e start), but th e sub-sam ple can be considered a pilot study to identify trends or suspected problem s, and it m ay inform the need for future study.
A ppropriate sam ple sizes alw ays need to be calculated by use o f procedures like those described above-th ere is no single num ber fo r sam ple size th at w ill alw ays w ork fo r any survey. It is also im portant to recog nize th at sam ple sizes w ill be different fo r different surveys, and a sam ple size should nev er be selected sim ply because it w as used for another project. In SRS, all households are num bered and then a num ber betw een one and the total n um ber o f households (N) is selected th rough a random n um ber gen erato r (one is available in M icrosoft Excel: R A N D ()- N generates a random n um ber b etw een 0 and N ). C ontinue to select households by use o f random num bers until the desired sam ple size is reached.
In m ost cases, such a list w ill n ot be available, and Stratified S ystem atic Sam pling is recom m ended. F o r th is m ethodology, y o u w ill need to identify th e sm allest sub-areas w ithin th e survey area fo r w hich population data are available, such as com m unities, districts, or v oting blocks. T hese estim ates m ay be obtained from a statistical bureau (census data), the w ater utility (custom er data), or other sources. I f the num ber o f h ouseholds in each sub-area is not know n, it can be estim ated by dividing th e population by the average n um ber o f people p er household. T he n um ber o f households to be included from each sub-area is allocated proportional to size, w here, for exam ple, a sub-area containing 6% o f the households w ould be assigned 6% o f the sam ple size. A sam ple provided that the areas are relatively homogeneous and the starting point fo r each sub area is selected at random).
To reduce bias o f household selection, the first house to be visited should be determ ined by a random m ethod. O ne w ay to do so is to assign a num ber (1 -1 0 ) to each in terv iew er and let the in terv iew er select the first house on the basis o f counting th at n um ber from the closest house to the d ro p -o ff point. T he sam pling interval is then u sed to select subsequent households.
E very effort should be m ade to include all households selected. I f a house is u n occupied at the tim e o f a visit, th at house should be revisited later th at day or on another day. I f the house is perm anently vacant, i f the occupants decline to participate, or i f an adult is not available fo r in terv iew after m ultiple attem pts, th en th e next closest household should be visited. The n um ber o f non-respondent households should be recorded on a H ousehold V isitation L og Sheet, to be subm itted daily to the Survey C oordinator. A sam ple H ousehold V isitation L o g Sheet is provided as A ppendix F.

# R e c r u i t m e n t a n d T r a i n i n g o f t h e S u r v e y T e a m

# C o m p o s i t i o n o f t h e s u r v e y t e a m

# Data entry
O ne or tw o detail-oriented individuals should be hired to enter com pleted questionnaires into a survey database. It is p referable that data be entered on a daily basis in order to allow for prom pt addressing o f any am biguities th at m ay arise.
D epending upon the availability o f tim e, personnel, and funds, data should ideally be double-entered (entered by tw o separate persons), and any differences should be exam ined in order to m inim ize entry errors. I f double-entry is not possible, then data cleaning prior to analysis w ill need to be m ore extensive.

# T ran spo rtatio n service
A driver w ith good fam iliarity o f the survey area w ill be needed to transport interview ers to and from survey sites. D epending on laboratory arrangem ents, the driver m ay also need to tran sp o rt sam ples from the field to the laboratory. Inform ation th at w ill be appropriate fo r m ost surveys includes (but is not lim ited to) the follow ing areas:
- H ou sehold characteristics/dem ographics (age, education, socioeconom ic status, household size)
- W ater sources (for drinking and other uses)
- C onsistency and quality o f piped w ater service (pressure problem s, breaks in service)
- H ou sehold w a te r storage practices (tanks, buckets, pitchers, etc.)
- H ou sehold w a te r treatm en t (bleach, boiling, filters, solar, etc.)
- P erceptions (about w ater quality, custom er satisfaction, health risks)
- C osts o f w a te r service (paym ent system , m eters)
- Sanitation and hygiene (toilet type, handw ashing, etc.)
- H ealth problem s o f household m em bers (diarrhea, skin infections, access to care, etc.)
- W ater quality-chlorine residual in delivered and stored household w ater B elo w are som e suggestions for analyses that m ay be o f interest to a W S P survey report. T hese analyses m ay n ot b e relevant in all contexts, and there w ill likely be additional param eters o f interest to each W S P survey report.
- B asic description o f the w ater utility, service, and consum er population
- D escription o f targ et area (rural vs. urban, socioeconom ic status, specific challenges related to w ater acquisition, industry, etc.)
- D em ographic characteristics o f survey respondents: age, gender, fam ily size, education, etc.
- P roportion o f population connected to m unicipal w ater system
- W ater sources (tap, w ell, rainw ater collection, etc.)
- C onsistency o f w ater service; breaks in service or pressure
- A lternative w ater sources u sed w hen system is not functioning

# R e p o r t i n g a n d p r e s e n t a t i o n o f r e s u l t s
R eporting o f survey results should roughly follow the survey instrum ent, describing dem ographics, w ater sources and service, including alternative w a te r sources, household storage and treatm en t practices, sanitation and hygiene, costs, com m unity concerns and health. W ater quality results-chlorine residual, m icrobiology, or othershould be reported separately fo r sam ples tak en directly from the tap, from household storage tanks, or from drinking w a te r containers, and the results should be com pared to identify differences in chlorine residual or coliform contam ination.

# A p p e n d i x A -S e c t i o n -b y -S e c t i o n S u m m a r y S u r v e y P l a n n i n g
C h e c k l i s t

# NOTE: This is an example from a low-resource setting provided fo r illustration only; estimates should be based on actual costs in the area where the survey will be conducted A p p e n d i x B -S a m p l e B u d g e t E s t i m a t e f o r W S P H o u s e h o l d S u r v e y

# A p p e n d i x C -S a m p l e I n f o r m e d C o n s e n t f o r W S P H o u s e h o l d S u r v e y
A sk to speak w ith fem ale head o f household (if not available, m ale head o f household is ok).
"H ello, m y nam e i s __________ and I am w orking w ith the (agency/ies carrying out the survey). W e are conducting a survey to g et a better understanding o f w ater use practices, the consistency o f w ater service, com m unity concerns, and health in (City/town location of WSP).
Y our house w as selected at random . The survey is anonym ous and w e w ill not collect any nam es or addresses. The questions in the interview do n ot ask anything private and you can choose not to answ er any question. P articipation in the survey is com pletely voluntary. Y ou are u n d er no obligation to participate, b u t y o u r responses w ill help us to understand the potential issues relating to w ater service in (City/town). The survey should take about 20 m inutes. W e w ill also collect sam ples o f y o u r tap and drinking w ater fo r testing. W ould you like to participate? I f you have any questions later, you can contact the (provide telephone number o f appropriate contact, e.g. health department, water utility, etc.) at (provide correct local phone #)." I f "no" , th an k the respondent and go to the next house (check " choose not to participate" box on log sheet). I f "y e s" , beg in questionnaire below .

# A p p e n d i x D -M e t h o d f o r C a l c u l a t i n g S a m p l e S i z e f o r a W S P H o u s e h o l d S u r v e y
O ne relatively sim ple m ethod for calculating survey size is to use the " sam ple size and pow er" calculator for a "population survey" in the StatC alc function o f E pi Info (this free softw are can be dow nloaded from the CD C w ebsite: h ttp w w .cdc.gov/epiinfo/) . The StatC alc option is found u n d e r the "U tilities" heading. The program w ill prom pt for entry o f (1) the population size, (2) the expected frequency o f the outcom e variable y o u select, and (3) the "w o rst acceptable resu lt" .
P o pulation size w ill usually be know n, or it can be obtained from the census bureau, the M inistry o f H ealth, or other governm ental or non-governm ental agency.
F o r estim ation o f the expected frequency o f a health-based outcom e variable (like diarrhea), clinic, hospital, or surveillance data should be used, w here available. P ublished studies or country estim ates can also be u sed i f they are related to a population com parable to the survey population.
T he "w o rst acceptable result" defines the lim it w ithin w hich a difference can be determ ined. F o r exam ple, fo r a household survey in a developing country w ith diarrhea prevalence estim ated at 15%, it is reasonable to define a difference b etw een the observed and expected values w h en a value that is 5 percentage points higher or low er than the expected value is observed-in this case, a prevalence o f 20% or 10%. T he standard confidence lim it used is 95% (alpha = 0.05). In other w ords, i f a "w o rst acceptable result" o f 10% is put into the m odel, assum ing a 15% expected prevalence o f diarrhea, w e are asking how m any subjects w ould need to be included in the survey in order to detect a difference o f diarrheal prevalence in the surveyed population o f at least 5% from the expected prevalence based on country data, w ith 95% confidence and 80% pow er.
T he E pi Info screens b elo w provide an exam ple o f calculating sam ple size for a population o f 155,555, w ith an expected diarrhea frequency o f 50% (this assum es a w orst-case scenario), in order to detect a difference o f five percentage points from the expected value (entering 45% or 55% w ould give the sam e value). T he sam ple size, given these values and a 95% confidence lim it from the chart below , is 383 households. A dding approxim ately 10% to account for non-respondents (increase i f a greater n um ber o f non-respondents is expected), the targ et should be 422 households. V .
3 8 3 9 9 6 6 1 9 9 . 9 v. 1 , 0 7 5 9 9 . 9 9 V . - P ilo t study-half-day field practicum (this data w ill not be included in actual survey) - R ev iew o f practicum , troubleshooting, questions - Final edits to questionnaire T he follow ing sam ple questionnaire w as designed based upon the conditions and issues o f potential concern th at w ere revealed th rough pre-survey planning. It w as u sed as a tem plate fo r various household surveys fo r W S P s in resource-lim ited settings w ith an organized piped w ater supply system in the C aribbean and L atin A m erica. P opulation size o f the surveyed areas ranged from 30,000 to 120,000. M o st households received w ater directly to th eir hom es from a piped w ater supply system . O thers had y ard or shared taps, or they used w ater from rivers or rain. F o r each targ et area, there w ere areas th at w ere n ot connected to the m unicipal w ater system or th at had unauthorized connections. Storage in household storage tan k s and secondary treatm ent w ithin the hom e w ere com m on as a result o f frequent interruptions in w ater service and pressure.
Som e questions contained in this sam ple m ay not be relevant to a given setting, or there m ay be other p ertinent inform ation th at is not included here. Q uestions th at w ill not contribute to the rep o rt should not be included. N otes on survey questions are em bedded in the questionnaire in blue print. A lternatives fo r som e questions are also provided. If, fo r exam ple, surveyors are typically invited into the hom e during the survey, som e questions m ay be replaced by direct observation. T hese alternative questions are also em bedded in the tex t in blue print.  Ask the following questions if there is heavy reliance on household storage tanks in the study community. T h a n k y o u v ery m uch fo r ta k in g part in th is in te rv ie w