What are the best ways to treat rainwater for drinking?

Here you can find some methods for making water safe for drinking: http://www.trailspace.com/articles/backcountry-water-treatment-part-4-methods-for-making-water-safe.html.

It depend on the collection and the location of the rain water.

Just Micron filteration, pH Correction and Ozonization, is enough for drinking purpose.

Water collection and then begin operations and the addition of material deposition abrasive deposits

hi, the simpelest way is the primary filteration then use UV .

to treat rain water for drinking apply the following u.o and u.p :- collection -screening - chemical settling using coagulation/flocculation processes - sand filtration - chlorination - storage and pumping.

1st   stage   ::::   collection of  water    

2nd stage  ::::   determination   the  physical  and  chemical properties 

3rd  stage  :::  knows how many water i need daily

4th  stage  ::  in this  case  i can  choose  way of treatment 

طبعا من السهل معالجه مياه الامطار بتجميعها داخل خزان كبير ويتمحقن كلور على هذه المياه داخل الخزان وبعد ذلك نأخذ المياه بالطلمبات لتمر على فلتر رملى لنزع الشوائب المواد الصلبه فى المياه ثم بعد ذلك فلتر كربونى لنزع الكلور واى غازات او رائحه غير مرغوب فيها من المياه ثم للقضاء على اى بكتيريا ممكن تتكون بعد عمليه الفلتره U V المرحله الاخيره قبل الاستخدام مباشرا يتم وضع جهاز

It depends on location. Pollution in the rain water is exactly the pollution of air in that area, but the must important point are dust and acidic matter, if the location is near the big sities both are important together, if the location is far from the big sities dust is the pollution. So Most of pollution in the air near the cities is CO2, so H2CO3 would be in the water, and also dust, in this situation you can treat the water with diffrent filters or use the lime and soda. If the location is far from the cities, air pollution might be just dust (There is no CO2 or other toxic gasses), so you can use just a sand filter or sedimentation method

1.  Ceramic filters.  These are a highly accessible technology in most communities where I've worked and often build nicely off of local potting knowledge.  Alternatively, in most medium sized towns, they sell candle filters that are easy to use and just need to be changed regularly.  In many cases, people mix very low doses of chlorine to ensure that the filter is working correctly.2.  Bio-sand filters.  These often require a specialist to build and install (the sieves to sort out the size of sand for the different layers are typically special orders, so people won't buy them unless they are building many bio-sand filters) and a training to ensure that they are used correctly.  However, in areas where they are available, they are a great way to produce reliably clean water.3.  SODIS.  Solar disinfection is one of the easiest and cheapest methods of water treatment, but it is also very easy to do it wrong and drink dirty water.  The idea is to put the water in transparent plastic containers (most places I've worked have a surplus of old plastic bottles from bottled water and soda, so these are freely available) and leave them in the sun for24-72 hours (depending on local conditions).  The sun will provide a free source of UV radiation to treat the water, though the bottles may need to be regularly replaced so that the plastic won't degrade.

the best way is treated by filteration method by rapid sand filter or pressure sand filter and then disinfiction by chlorine dioxide or U.V lamp