Aging and leaking water infrastructure wastes water resources and creates public health risks. Upgrading of potable water systems represents a large financial burden for water utilities and private property owners. The conventional approaches of repair, rehabilitation and replacement are very effective, but will take decades to implement even if a financial commitment to do so was made immediately. A novel approach of in-situ remediation of leaks, achieved by harnessing the ability of water or pipe to repair leaks via clogging, could potentially reduce leak rates and extend the lifetime of existing infrastructure at relatively low cost and inconvenience. Physical clogging, precipitation and metallic corrosion were identified as major mechanisms of in-situ leak remediation in potable water pipelines. Autogenous repair (i.e., self-repair without added particles) of small leak-holes (150–"1000 μm) in copper and iron was validated in the laboratory at water pHs of 3.0–11.0, operating water pressures of 20–60 psi, upward and downward leak orientations, and for a range of water chemistries. In bench scale experiments, the time to repair of iron pipe leaks increased with leak size to the power of 0.89–1.89, and decreased with pipe wall thickness to the power of -1.9 to -1.0. The time to repair of copper pipe leaks increased with water pressure to the power of 1.7. Additionally, the waters with a higher DO and corrosivity as measured by RSI, significantly decreased the time to repair of carbon steel 400 μm leaks by 50–70%. The presence of chlorine dioxide significantly increased the fraction of repaired 200 μm copper pipe leaks by 3 times when compared to the control without any disinfectant. In the building scale study, the fraction of repaired iron pipe leaks decreased with the logarithmic leak size with a slope of -0.65 after one-year duration of experiments, while leak orientation and water pressure were not influential in time to or likelihood of repair for iron pipe leaks. Addition of calcium carbonate particles (~8.8 μ]m), silica particles (~29 μm) and wood ash particles (~160 μm) in Blacksburg, VA tap water at a water pressure of 10 psi increased the fraction of remediated iron pipe leaks of 280–1000 μm diameter sizes. Although the control condition with no added particles for 58 days resulted in remediation of 0/12 leaks, remediation rate increased to 1/12 with calcium carbonate particles, to 10/12 with silica particles and to 10/12 with wood ash particles. Leak size and particle size played an important role in controlling the remediation success rate. The strength of the in-situ leak repair was sometimes very strong and resilient. The sealing materials of leak-holes repaired at 20–60 psi could sometimes withstand a 100 psi water pressure without failure, demonstrating the potential of the approach to sustain aging and leaking infrastructure. In-situ leak repair can also occur naturally, and the success rate might be unintentionally altered by adjustment of chemistry or treatments that decrease or increase particulates. / Ph. D. / Old and leaking pipes waste water resources and can contaminate water. Upgrading of drinking water systems represents a large financial burden for water utilities and home owners. The traditional approaches to repair or replace the leaking water pipes are very effective, but will take decades to implement even if a financial commitment to do so was made immediately. A new approach of leak remediation, achieved by changing the drinking water chemistry, could potentially reduce leak rates and repair water leaks while in use without digging up the buried water pipes. Therefore, leak remediation could extend the lifetime of existing infrastructure at relatively low cost and inconvenience, and may be necessary if society cannot afford pipe replacement. Recent field observations indicate that metal corrosion, one type of reaction that eats up water pipes and causes water leaks, could clog the leaks via the corrosion products. And the repair in most cases could last for a long period of time. Our work was the first to reproduce the field observations in the laboratory, revealing that water pipe leaks could be successfully clogged or remediated by natural corrosion reaction products, if the water chemistry is favorable. Additionally, our work also showed that water leaks could be clogged or remediated by addition of water particles to drinking water, which was practiced by Roman engineers a long time ago. There are legitimate health concerns about particulates because they are indicative of microbial risks, but addition of particulates to water at low levels might heal pipes without such concerns. We also proved that in some cases the repaired materials clogging the leaks could withstand a very high household water pressure, showing that the sealing materials in water leaks repaired with natural corrosion products or added water particles could create long term repairs. With improved practical understanding this approach might be usefully applied, either intentionally to repair existing leaks, or make sure that changes to water chemistry do not unintentionally make problems worse.