Updated on January 16, 2024


Created on August 27, 2015

Solvatten Solar Safe Water System

A water purifier and heater aimed to reduce a household's dependency on heating water over a fire.

Developed By
  1. Solvatten
Tested By
  • BioVir Laboratories
  • U.S. Environmental Protection Agency
  • Water Quality Laboratory Gaborone, Botswana
Content Partners


Product Description

Solvatten® is a combined portable water treatment and solar water heater system that has been designed for use at the household level. It is designed to insulate and also store heated water. This Solar Techonology reduces the need to heat and boil water by burning firewood or charcoal therefore tackles climate change by reducing carbon emissions in average 1,5 tonnes/ year and 10 tonnes per lifetime use. It is also designed withthe purpose of reducing expenses for the urban poor and so improving lives inKenya’s urban slums.

This product is designed and produced by Solvatten, a Swedish social enterprise with base in Stockholm.

Target SDGs

SDG 6: Clean Water and Sanitation

SDG 7: Affordable and Clean Energy

Target Users (Target Impact Group)


Distributors / Implementing Organizations

Solvatten is currently active in 45 different projects with various international partners and NGOs. Collaborators and partners include: PLAN International, International Aid Services, UNICEF, NRC, SOS Children's Villages, UNFCCC, OXFAM, UN Habitat, WWF, SIDA, EXPORT RÅDET, AMREF, Child Fund, ALMI,LIONs Sweden, SLU, KTH, Uppsala University VINNOVA, WHO, VI Agroforestry, IVL, My climate, IEW Kenya, Ministry of Environment Haiti, Kopernik, Svenska Kyrkan, LWF, Tillväxtverket, PhilMedAlliance, Impact Carbon, U&We, CHAIN Uganda, ECO ARKI Peru, Urban Way, RINCOD, Rotary and many more.

Competitive Landscape

Direct competitors include SunSaluter and Solarbag.

Manufacturing/Building Method

Mass produced. Solvatten® is manufactured in Sweden in compliance with ISO 14001 and ISO/TS 16949 (Environmental and Quality certifed).

Intellectural Property Type


User Provision Model

Solvatten® is available for purchase online. For purchasing larger quantities for projects in developing countries, it is recommended to contact the sales team directly.

Distributions to Date Status

Today, Solvatten® is used in more than 20 countries around the world reaching more than 260,000 people.

Description of the combined methods

Filtration, solar disinfection

Manufacturer-specified water treatment rate (L/hr)

10 L, 2-6 hr treatment

Bacteria reduction

7 log

Virus reduction

>5 log

Protozoa reduction

>5 log (cyst)

Heavy metals and/or arsenic reduction


Maximum recommended influent turbidity level (NTU)


Effluent turbidity levels (NTU)



Safe water storage capacity (L)

10 L

Manufacturer-specified lifetime volume (L)

42,000 to 100,000 L



Design Specifications

Solvatten® is a portable 10 liter container that utilizes solar energy to heat and treat water at the household level. The unit does not require chemicals, spare parts or other supplies. Solvatten® works by incorporating three established methods for treating water; • Filtration: water is poured in through a hole housing a fabric filter that catches larger particles. • Heat pasteurization: heat from the sun warms up the water, killing pathogenic material. • UV-disinfection: The high energy associated with UV sunlight causes damage to the DNA of micro-organisms, rendering them unable to reproduce or infect. Users must expose the Solvatten to 2-6 hours of direct sunlight to achieve water that is treated within the ‘Highly protective’ category defined by Swedish Cleantech. Under optimal conditions, Solvatten can be used four times a day and treat up to 40 Litres of water per day. The unit does not work effectively during heavy cloud cover or rain. The SVI-10 indicator shows when the water is safe. In addition to safe water, Solvatten heats water to up to 75°C for household and hygiene purposes, such as cooking, hand washing, bathing and domestic cleaning. The Solvatten dimensions are 360 x 470 x 130 mm and it weighs 2.70 kg unfilled.

Product Schematics

Technical Support

Solvatten® provides guidance related to operation via graphic instructions that are printed on the unit. To date they have printed instructions in English, Spanish, French, Portuguese, Urdu, Hindi and Swahili. Technical assistance services are not indicated.

Replacement Components

The unit is made of plastic materials which are durable to heat and UV resistant and UV transparent. The materials used are FDA-certifed and recyclable. The only part that may need replacing is the which can be replaced with a folded piece of locally sourced cloth.


On average, a Solvatten® unit lasts seven years, but if handled with care it can last much longer. If a family uses Solvatten for seven years, treating 20 liters of water for 330 days a year, they will produce 46,200 Liters of safe water. The unit includes a 1 year full warranty against manufacturing defects, on condition the customer has followed the use and care instructions provided.

Manufacturer Specified Performance Parameters

Under optimal conditions Solvatten® can be used four times a day and treat up to 40 Litres of water per day. Solvatten heats water to up to 75°C for household and hygiene purposes. Safe, warm water is achieved in 2-4 hours, when the sun is shining, 5-6 hours when it is partly cloudy.

Vetted Performance Status

Solvatten® has been tested using samples containing more than 200,000 colonies/100 ml – the results of this test showed that the treated water met the WHO’s safe drinking water standards of less than 1 colony/ 100ml. Solvatten® can treat highly resistant forms of bacteria, viruses and parasites. USEPA certified tests conducted in California in 2014 showed that water treated by Solvatten® reached the ‘Highly protective’ category, eliminating parasites, virus and E-coli. By comparison, chlorine and most filters are not able to achieve this level of protection. Laboratory testing against E. coli, faecal coliforms, faecal Streptococci and total coliforms conducted by Water Quality Laboratory Gaborone, Botswana. Department of Water Affairs (2013) showed acceptable water quality for human consumption.


Improper use of Solvatten® is a risk of exposure to harmful microorganisms and increase your risk of gastrointestinal illness. Never use Solvatten® to filter seawater or chemical contaminated water, including water from mining tailing ponds or from near large agricultural operations. The efectiveness of Solvatten® may be limited by environmental or hygiene conditions that could contribute to the recontamination of water after it has been treated according to the instructions. These conditions include but are not limited to: • Using water from Solvatten® with dirty and bacterial contaminated hands. • Storage of treated water in contaminated containers. • Treatment of water with high turbidity (> 40NTU) without pre-filtering the water. By using Solvatten®, you tacitly accept and agree to the term and conditions of the user instructions and the Disclaimer (1.2) 2016. Solvatten® recommends cleaning inside periodically, so that it continues working efficiently by simply adding a handful of dry beans, rice or lentils and some water to the unit, before shaking and rinsing. Soft woolen balls are another alternative here. Do not use sand, as it may scratch the surface, and do not use detergents. Solvatten® is manufactured in compliance with ISO 14001 and ISO/TS 16949 (Environmental and Quality certifed). Environmental Footprint Reference: LCA Master Thesis by KTH/ The Royal Swedish Technical University 2011.

Complementary Technical Systems


Academic Research and References

Lundström H & Hagström E, 2012, A field study in Kenya of isolation parameters to make water drinkable in the household water treatment unit Solvatten. Uppsala University, Uppsala. not peer reviewed

Jönsson, J., Wikman, A., and Wätthammar, T., 2011, Social Return on Investment, SROI, the value added for families before and after using Solvatten in the Bungoma district in Western Kenya, First cycle, G2E. Uppsala: SLU, Dept. of Economics.

Isberg, U., and Nilsson, K., 2011, Life Cycle Assessment and Sustainability Aspects of Solvatten, a Water Cleaning Device, dissertation, KTH, School of Architecture and the Built Environment (ABE).

“Projects,” Sunshine Stories, 09-Apr-2020. Available: https://solvatten.8190.nu/projects-2/ 

“Shop,” Sunshine Stories, 20-Mar-2020. Available: https://solvatten.org/shop-2/

Household solar water treatment and solar water heater system, “Solvatten – Solar Safe Water System, SSWS-10,” Engineeringforchange.org. Available: https://www.engineeringforchange.org/wp-content/uploads/2015/08/Product-Specification-2019.pdf 

Goal 6. (n.d.). Sdgs.un.org. Available: https://sdgs.un.org/goals/goal6 

“What is Solvatten?,” Sunshine Stories, 28-Jan-2020. Available: https://solvatten.org/what-is-solvatten/ 

“Om oss,” Sunshine Stories, 28-Jan-2020. Available: https://solvatten.org/about-us/

U. S. Epa and OA, “U.S. Environmental Protection Agency,” 2013. https://www.epa.gov/

“Locations – IEH Laboratories & Consulting Group – The Institute for Environmental Health – Food Safety Laboratories, 15-Mar-2022. Available: https://www.iehinc.com/locations/ 

P. Wadström, C. Solvatten, and R. Danielson, “TO: Petra Wadström, CEO Solvatten AB,” Engineeringforchange.org. Available: https://www.engineeringforchange.org/wp-content/uploads/2015/08/Biovir-testresultat.pdf

Compliance with regulations

Water treated by Solvatten® falls into the  U.S. Environmental Protection Agency (EPA)  Highly protective category. The materials used to make Solvatten® are fully approved by the FDA. Meets the WHO’s safe drinking water standards of less than 1 colony/ 100ml.

Evaluation methods

• Laboratory assessment conducted by Biovir Laboratories for virus, bacteria and Cryptosporidium reduction in two challenge waters.(2014)   • Laboratory testing against E-coli, faecal coliforms, faecal Streptococci and total coliforms. Conducted by Water Quality Laboratory Gaborone, Botswana. Department of Water Affairs (2013)   • Field trials were conducted by UN-habitat (2008) to assessing the effectiveness of Solvatten in Kathmandu, Nepal

Other Information

In 2013 Petra Wadström won the prestigious Polhem Prize for her invention Solvatten. Solvatten AB received the SACC New York- Deloitte Green Award 2011.

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