The more people live in one place and the greater the level of urbanisation, the more important a sound water supply is. What is meant here is not merely general availability, i.e. the availability of sufficient quantities of high-quality water that does not represent a health risk. What is also meant is the installation of an intact storage and piping system, in order to be able to transport fresh water to the place where it is needed free of undesirable pollutants and odorants and to take waste water away again without any leakage loss.
In the Roman Empire, aqueducts were a common sight both in towns and out in the country; some of these extremely impressive structures still exist today and testify to the architectural skills of the era in which they were built. Nowadays, most water pipes are installed underground and, in houses, concealed underneath plaster. When corrosion and leakage occur due to wear and tear, which can always be expected after a certain amount of time in systems that transport liquids, repairs are essential, in order to limit liquid loss as well as the extent of collateral damage. While it is comparatively easy to carry out maintenance work on pipe systems that are above ground, laborious excavation work can be expected if water pipes under streets or in-house walls have to be reached.
The amount of work and expense needed can, however, be reduced if complete sections of piping are repaired rather than – quite literally – plugging individual holes, with the help of liner technology (relining) that does not require complex construction work. In this process, a liner impregnated with epoxy resin made, for example, of felt is pulled into the entire length of the corroded pipe. Experts are of the opinion that this CIPP principle is just as reliable as a completely new water pipe where imperviousness and load-bearing capacity are concerned, as soon as the epoxy resin has cured completely. Pipes can also be coated directly with epoxy resin, which is only advisable inside houses, however, due to the lack of additional stabilisation by an appropriate liner.