Towns relied primarily on natural watercourses for the water they used in cooking and drinking. Unfortunately, they relied on the same watercourses for sewage and for cleaning items that were soiled or were in process of manufacture. The king's injunction to the Oxford brewers in 1305 was not their first warning, for in 1293 both brewers and bakers were prohibited from taking water from the Trill mill stream, on the grounds it was polluted.

As urban populations expanded rapidly in the thirteenth and early fourteenth centuries, placing heavier competitive and conflicting demands on the water supply, civic authorities were obliged to pay more attention to assuring the availability and quality of water. Their concern was with a wide spectrum of issues: not merely drinking water, but sufficient flow to carry off sewage and to power mills, and ensuring the navigability of waterways (jeopardized by such things as dumping of garbage, silting, and placing stakes, weirs or other obstacles). Public hygiene – was, however, one dimension of what became one of the chief preoccupations of urban administration, although water quality was only one component of hygiene. For instance, the Coventry injunction of 1421 against dumping dung or industrial refuse in the river and the orders to clean out rivers, brooks, and ditches and to remove any privies or aqueducts impacting on the watercourses, are part of a much larger set that the mayor had proclaimed publicly; this set also addresses the regulation of victuals retail, animals running loose in the streets, carrying of weapons, disposal of refuse, street cleaning, and other matters. Impure water likely played no small role in the high infant mortality rate, and must have been a factor in the general health of the populace.

When population experienced a downturn from the effects of recurrent plague during the second half of the fourteenth century, the problem was not lessened, for popular suspicion associated the epidemics with polluted water and poor sanitation, causing the authorities to clamp down further on unsanitary practices and make greater efforts to protect the water supply. Possibly social changes stemming from depopulation (stimulating greater artisanal assertiveness) and disruption in governmental and policing functions encouraged greater flaunting of convention on the part of some townspeople.

Much of the surviving primary documentation on this subject focuses on suppression, punishment or regulation of such practices. The formative period of civic self-government, as illustrated principally through charters and custumals, shows concern primarily with constitutional and administrative details, and little with matters of sanitation and water supply; but once more routine records emerged as administration developed, we start to see growing attention given to the subjects. We should, however, beware of concluding from this evidence that medieval towns were filthy, smelly and unhealthy. By modern standards they were, some neighbourhoods more than others, but those same records indicate public dissatisfaction with unsanitary conditions and the attempts of authorities to bring the problems under control. Nor should we assume that offences documented in surviving court records are simply the tip of an iceberg, or that regulations against a misbehaviour were prompted by widespread abuse – still today a few instances, or even a single notorious case, can suffice to prompt an administration to enact a control.

In their efforts to control, however, the politicians had to recognize the diversity of community needs and strike a balance between them. Even though abuses were due to a minority, the authorities also came to recognize that suppression might not be feasible and that a more viable solution would be to regulate behaviour while at the same time taxing it to create a revenue stream that could then be applied to improving the system. When occupational groups were fined en masse for some offence against the community, this may be more a case of licencing than universal culpability.

The above texts show some of the uses made of the water supply. Both private individuals and occupational groups could be careless or negligent in their treatment of watercourses; cloth-workers and leather-workers needed a good supply of water for their industrial processes, while butchers and fishmongers needed water for cleaning. Given the poor state of medical knowledge in the Middle Ages, a connection (other than very general) between water quality and public health may not have been evident to many, but senses of smell and taste indicated to most when something was badly amiss or hazardous, and it could not have been hard to associate bad-tasting water with ensuing bouts of fever or diarrhea.

Juliana atte Floude appears to have been making use of the Shulworth Street watercourse for her occupational activities; she may have been a spinster or more broadly involved in the cloth-making cottage industry. The stream here, the Kingsbrook, appears to have had a particular importance in the Winchester water system, perhaps due to an earlier association with the royal palace before that was abandoned and the stream's course diverted. This was a part of the city where there was a close association between the watercourses and workshops, and the neighbourhood was in the early modern period known as "The Brooks".

It may be that the pair Juliana accused of interfering with her use of the watercourse were city officials, as the final part of the text seems to imply that they could continue to exercise supervision in regard to abuses specified (one presumes) by city ordinance. Or possibly the pair were supervisors of the dyers' craft, just as the masters of the butchers were implicitly made responsible in the 1409 ordinance for ensuring butchers acted responsibly in their use of the watercourses.

The exceptions noted by the jury considering Juliana's complaint were based on documented abuses. Abuses that continued throughout the fourteenth and fifteenth centuries, as presentments in the city court indicate.

A city ordinance of 1416/17 required that

in future all dyers, or anyone else of whatever social status or position, who between sunrise and sunset casts or has [someone else] cast any vat of woad or, as it is called, wodger into the king's stream at Winchester, before nightfall, is to be amerced 6d. Which 6d. is to be levied by the officers of the court from his goods and chattels, to the use of the bailiffs, without any demur or delay; and he should be amerced as often as he may be discovered, or known, or proven, to be in default between sunrise and sunset.
[The Black Book of Winchester, 8]

The Winchester ordinance of 1409 seems to be placing the onus on the butchers to be self-policing in regard to irresponsible dumping of slaughterhouse by-products into the public waterways. The concern here was not with dumping per se, but the fear that if the dumping was not done properly, the offal would not be washed down into the river but would accumulate, blocking the watercourse. Blockage could result in filth accumulating or, worse, in it flooding out into neighbouring houses and streets in times of heavy rain. This impression about dumping is reinforced by a brief enactment of 1489, warning that "if any man casts any dung, straw, dead pig, dog or cat or any other filth into a watercourse, so that the flow of water might be stopped, he shall forfeit 12d." [Black Book of Winchester, 121]. The butchers were also unpopular for dumping blood or bloody water onto public thoroughfares: not only was it offensive and smelly, but also slippery for pedestrians. For example, in 1429 butcher Henry Coupere and his servants were punished for washing out containers of animal blood at a public well near the butchery stalls, and leaving the bloody water in the street.

Essentially the same ordinance as that of 1409 was promulgated anew in 1513. On this occasion there was no mention of the craft-masters' liability, but we do hear that a location called Abbess' Bridge (Colebrook Street) had been assigned for the offal – duly cut up – to be dumped. We know that by 1370 there was an assigned location, and perhaps it was the same. The water at that location was fast-flowing and would have avoided contaminated water passing through the cathedral priory, which would have caused complaints. However, butchers often did not bother to cart offal down the highway to the assigned dumping-place, and so the priory faced getting its drinking water from a polluted source until the late fifteenth century, when a piped supply was provided.

Butchers represented one of the more difficult and persistent problems for civic authorities because the nature of their work gave rise to a good deal of unpleasant refuse to be disposed of, and butchers preferred to be active within the more populated areas of a town, where their clientele was. Industrial crafts such as tanning and dyeing, by contrast, did not need to be in the most populated areas of town, although they did need good access to water. Some authorities legislated the removal of such occupations to less densely populated areas.

London butchers, who not only sold meat in the local shambles (of which there were three) but also slaughtered animals there, were frequently prosecuted for defiling the streets with blood and offal, or for dumping it carelessly at the edge or on the banks of the Thames, or in excessive amounts in the streams causing blockages, as well as for selling putrid meat and generally for causing such a stench with their activities that it drove people away, either in disgust or from fear of contagion. Owners of scalding-houses, where body hair was removed from carcasses, were similar offenders. Ernest Sabine ["Butchering in Medieval London." Speculum, vol.8 (1933), 335-53] has given a good account of the authorities' efforts to deal with such problems in the fourteenth century.

It was expected that these trades would dispose of blood, dung, and entrails in the tidal waters of the Thames, directly or indirectly; but, if the former, they were required to take it to the riverside by specified routes and to dump it at ebb-tide only. In 1343 the butchers of St. Nicholas Shambles were granted a segregated spot on the bank of the Fleet, from where their refuse could be washed into the Thames, purportedly to discourage them from dumping outside the house of the Greyfriars; this had to be relocated to the Thames bank itself, after the Prior of St. John of Jerusalem complained of the stench. The new location became known as Butcher's Bridge.

In 1361 – in the context of renewal of the plague – the king, with the backing of parliament, reflected public concern through a general complaint to the city authorities about the risk to public health of animal blood flowing through the streets and into open sewers and of the noxious humours arising from the Thames due to dumping of offal. The Thames was of course a highway for the king and other nobility between Westminster and the Tower, so London must have experienced greater external pressure than other towns to institute sanitary reforms. Slaughter of beasts was moved outside the city, but the butchers gradually resumed their old practices. With another outbreak of plague in 1369, the butchers were again ordered outside the city and Butcher's Bridge was demolished. The Coventry injunctions of 1421 similarly prohibited the slaughter of beasts within the city walls, excepting pigs (for which a scalding-house was in process of construction, and scalding was thereafter restricted to that location). Butchers of the shambles at East Cheap and the Stocks had less of a hard time, the latter using the Walbrook – which had become little better than an open sewer – and the former being closer to the Thames, with fewer householders to offend; the western half of the city had more wealthier residents to make a noise.

New regulations in 1392 provided for a new facility, at Queenhithe, where butchers were to cut up their offal, carry it in boats out to mid-stream, and dump it there at ebb-tide. By the close of the century a system was in place that seems to have reduced the problems, or at least lessened the regularity and vocality of complaints – the gradual disappearance of the plague perhaps also being a factor in the greater quiescence.

Availability of a good natural water-supply was one factor in determining the placement and growth of human settlements, but townspeople did not rely exclusively on that. They also sought out springs in the vicinity – FitzStephen noted several that provided Londoners with relatively good quality drinking water; they sunk wells, both private and public – two of the latter being visible in the 16th-century plan of Yarmouth, one of them in the marketplace, which was a fairly typical location for a communal well; and they dug ditches, sometimes using existing streams flowing into the principal river. At Salisbury inadequate access to water became part of the excuse for the bishop to move his cathedral, from an ancient hill-fort that rose well above the water-table and the reach of wells, and establish a new town under his lordship beside the river, a mile and a half distant. The opportunity this provided for town planning during the 1220s included the provision of a water system: New Salisbury's streets, laid out in a grid pattern, had as an integral component water channels drawing water from the river (initially fed from a trench cut to power a mill) that ran along the main streets, on gradients facilitating the continual flow of the water. Speed's map shows the water system clearly.

It has been said that New Salisbury was exceptional. Yet it may be that Winchester provided some inspiration for the scheme. This ancient capital of England also had by the late Middle Ages a pattern of watercourses that so closely matches the street grid as to suggest the pair may have developed in tandem, around the late ninth century [Derek Keene, Survey of Medieval Winchester, vol.2, Oxford: Clarendon Press, 1985, 56]. Again this system may have been partly intended to power some of Winchester's water-mills, of which there were at least nine to serve the public and another four serving religious communities in the town; most of the public mills were on the River Itchen itself, but a few were on streams and faced growing difficulty as the flow of the streams became impeded.

Archaeological investigation has shown that by the eleventh century some householders had dug channels leading from the streams closer to the fronts of their own houses; sometimes the houses were later extended to go above the private channels, thus providing a form of interior running water. Archaeologists have also found a number of medieval wells, some possibly pre-dating the artificial watercourse system, some post-dating it (construction prompted probably by stream-water being too polluted to drink), while others were on higher ground not served by the streams.

Just as at Coventry and Henley, it was the responsibility of Winchester owners or tenants of properties adjacent to the streams to keep them in good shape. The documented practice in the sixteenth century of once a year repairing the timber revetements of the banks and of scouring the stream beds also seems to have been done as early as the fourteenth century. This responsibility of householders living beside watercourses was fairly common in towns, although occasionally a larger unit such as the parish or ward is seen to have responsibilities. The same approach was taken regarding street maintenance.

Lynn provides another example of a town where a water-system was deliberately introduced. It might be suggested that the community had some involvement in water management as early as the salterns of the eleventh century; the development of the salterns contributed to the formation of wide streams leading away from the river, and these later became the source for a number of lesser water-channels in the planned northern sector of the town. Since most of these did not run along the streets but along the backs of properties, it has been proposed that they were primarily drainage ditches rather than a source of drinking water [Vanessa Parker, The Making of King's Lynn, London: Phillimore, 1971, 26].

We also have reference to a "communal lake", perhaps a reservoir, near the Gannock, where one of the streams intersected with the defensive (water-filled) ditch; in 1443 a townsman was fined for washing his sheep there, and in the same year the residents of South Lynn had been ordered to clean out the stream near Gannock. Perhaps this reservoir was the one created during the two consecutive mayoralties of John Permonter (1423-25) and intended for irrigation of the burgesses' extra-mural fields; Permonter's achievements also included repairs to all of the ditches, and pursuit of his predecessor's initiative to introduce a new supply of fresh water into the ditches, brought from land of the Prior of Lynn in Gaywood – Permonter had negotiated for a rent-free grant of 40' of land on either side of the proposed canal, and there remained negotiations with other owners of land along the route. In March 1430 Permonter, again mayor, returned from parliament with a new commission for the repair of the ditch around the town, the work to be undertaken by the residents of Lynn.

In contrast with the purpose of the Lynn ditches, the northern suburb of Bishopsgate had ditches paralleling the road interspersed with large settling tanks, and it has been suggested that this was therefore not merely drainage but an effort to provide useable water [Christopher Thomas, The Archaeology of Medieval London, Stroud: Sutton, 2002, 23], although foreign objects found in the ditches suggest the water was, or became, polluted. The city proper relied initially on large streams – the Walbrook within the walls and the Holborn/Fleet just outside, while the Tyburn and the Westbourne provided water for the western suburbs and Westminster – as well as the springs already mentioned, and of course the Thames itself, while the more prosperous citizens often had their own wells or cisterns for collecting rain-water.

Gutters along city streets were intended to carry liquid refuse into the watercourses; in the major streets of London the volume of water use may have been sufficient to create adequate flow for a drainage system. In other towns it may be doubted whether the volume was sufficient to keep sewage moving along gutters, where they existed. Like rivers, streams and ditches, the integrity of the gutters – both public and private – had to be regulated by civic authorities. Hilda Grieve reports that at Chelmsford in the latter half of the fifteenth century "Cases multiplied before the courts of nuisances arising from broken, blocked, or ill-directed rainwater and domestic gutters, which discharged into the street or bred discord between neighbours" [The Sleeper and the Shadows. Chelmsford: a town, it's people and it's past, Essex Record Office Publication no.100 (1988), vol.1, 86]. Domestic water, dirty from the washing of clothing or the cleaning of fish, might empty out of an upper storey of a house, sometimes soaking passers-by, or be poured into the streets creating a stench and sticky or slippery conditions (see prohibitions at Bristol).